
Contents
60.2 Clinical trial design: statistical issues
Get access-
Published:July 2018
Cite
Abstract
Randomized controlled trials are considered the gold standard for the evaluation of new therapies in terms of efficacy and safety. In the planning of any trial, the determination of the number of patients to be included (the so-called sample size) is a crucial step. This chapter explains how sample sizes are calculated for a variety of outcomes (continuous, binary, and survival) and designs (superiority and non-inferiority trials). The simple structure of the sample size formulae provides us with some useful rules of thumb. For instance, the sample size increases by a modest 12.5% if the randomization is not 1:1 but 2:1. A worked-out example based on cardiovascular trials using free software available for download is provided. Furthermore, concepts for dose-ranging studies aiming to identify the optimal dose to take forward in a clinical development programme are described. Cross-over trials are more efficient than parallel group designs, but their application is only appropriate under certain conditions which are explored in this chapter. More recently, adaptive designs have gained increased attention as they introduce more flexibility into clinical trials and clinical development programmes. Advantages and disadvantages are briefly discussed and recent trends are highlighted.
Signed in as
Institutional accounts
- National Science & Technology Library
- Capital Medical University
Sign in
Personal account
- Sign in with email/username & password
- Get email alerts
- Save searches
- Purchase content
- Activate your purchase/trial code
- Add your ORCID iD
Purchase
Our books are available by subscription or purchase to libraries and institutions.
Purchasing informationMonth: | Total Views: |
---|---|
October 2022 | 5 |
November 2022 | 3 |
December 2022 | 4 |
January 2023 | 3 |
February 2023 | 8 |
March 2023 | 9 |
April 2023 | 3 |
May 2023 | 5 |
June 2023 | 2 |
July 2023 | 5 |
August 2023 | 5 |
September 2023 | 2 |
October 2023 | 2 |
November 2023 | 7 |
December 2023 | 10 |
January 2024 | 12 |
February 2024 | 2 |
March 2024 | 4 |
April 2024 | 3 |
May 2024 | 1 |
June 2024 | 6 |
July 2024 | 2 |
August 2024 | 1 |
November 2024 | 1 |
December 2024 | 3 |
January 2025 | 2 |
April 2025 | 2 |
Get help with access
Institutional access
Access to content on Oxford Academic is often provided through institutional subscriptions and purchases. If you are a member of an institution with an active account, you may be able to access content in one of the following ways:
IP based access
Typically, access is provided across an institutional network to a range of IP addresses. This authentication occurs automatically, and it is not possible to sign out of an IP authenticated account.
Sign in through your institution
Choose this option to get remote access when outside your institution. Shibboleth/Open Athens technology is used to provide single sign-on between your institution’s website and Oxford Academic.
If your institution is not listed or you cannot sign in to your institution’s website, please contact your librarian or administrator.
Sign in with a library card
Enter your library card number to sign in. If you cannot sign in, please contact your librarian.
Society Members
Society member access to a journal is achieved in one of the following ways:
Sign in through society site
Many societies offer single sign-on between the society website and Oxford Academic. If you see ‘Sign in through society site’ in the sign in pane within a journal:
If you do not have a society account or have forgotten your username or password, please contact your society.
Sign in using a personal account
Some societies use Oxford Academic personal accounts to provide access to their members. See below.
Personal account
A personal account can be used to get email alerts, save searches, purchase content, and activate subscriptions.
Some societies use Oxford Academic personal accounts to provide access to their members.
Viewing your signed in accounts
Click the account icon in the top right to:
Signed in but can't access content
Oxford Academic is home to a wide variety of products. The institutional subscription may not cover the content that you are trying to access. If you believe you should have access to that content, please contact your librarian.
Institutional account management
For librarians and administrators, your personal account also provides access to institutional account management. Here you will find options to view and activate subscriptions, manage institutional settings and access options, access usage statistics, and more.