Table 2:

Common P-value misconceptions

MisconceptionAdequate interpretation
The P-value represents the probability of H0 being trueAs the P-value is calculated under the assumption that H0 is true, it cannot represent a probability of a hypothesis. Instead, it represents the probability of finding similar—or more extreme—data in future similar experiments, under the assumption that H0 is true.
The P-value represents the 1-probability of H1 being trueSimilarly, as the P-value is calculated under the assumption that H0 is true, it cannot simultaneously represent the probability that H1 is true.
A P-value >0.05 implies that H0 is trueAs the P-value is calculated under the assumption H0 is true, a P-value above 0.05 merely implies that similar or more extreme data would be observed in >5% of similar future experiments.
A P-value <0.05 implies that H1 is trueSimilarly to the previous two misconceptions, a P-value below 0.05 only represents the <5% probability that similar or more extreme data would be observed in such future experiments.
A P-value <0.05 implies that there is an important difference between groupsSmaller P-values represent the probability of the observed data under the null hypothesis, which can particularly occur in very large trials, although a treatment effect may be very small.
A P-value >0.05 implies that there is no difference between groupsLarger P-values simply represent that the observed data are still not that unusual under the null hypothesis, which may be particularly evident in smaller trials.
MisconceptionAdequate interpretation
The P-value represents the probability of H0 being trueAs the P-value is calculated under the assumption that H0 is true, it cannot represent a probability of a hypothesis. Instead, it represents the probability of finding similar—or more extreme—data in future similar experiments, under the assumption that H0 is true.
The P-value represents the 1-probability of H1 being trueSimilarly, as the P-value is calculated under the assumption that H0 is true, it cannot simultaneously represent the probability that H1 is true.
A P-value >0.05 implies that H0 is trueAs the P-value is calculated under the assumption H0 is true, a P-value above 0.05 merely implies that similar or more extreme data would be observed in >5% of similar future experiments.
A P-value <0.05 implies that H1 is trueSimilarly to the previous two misconceptions, a P-value below 0.05 only represents the <5% probability that similar or more extreme data would be observed in such future experiments.
A P-value <0.05 implies that there is an important difference between groupsSmaller P-values represent the probability of the observed data under the null hypothesis, which can particularly occur in very large trials, although a treatment effect may be very small.
A P-value >0.05 implies that there is no difference between groupsLarger P-values simply represent that the observed data are still not that unusual under the null hypothesis, which may be particularly evident in smaller trials.

Partly based on Goodman et al. [5] and Greenland et al. [6].

H0: null hypothesis, H1: alternative hypothesis.

Table 2:

Common P-value misconceptions

MisconceptionAdequate interpretation
The P-value represents the probability of H0 being trueAs the P-value is calculated under the assumption that H0 is true, it cannot represent a probability of a hypothesis. Instead, it represents the probability of finding similar—or more extreme—data in future similar experiments, under the assumption that H0 is true.
The P-value represents the 1-probability of H1 being trueSimilarly, as the P-value is calculated under the assumption that H0 is true, it cannot simultaneously represent the probability that H1 is true.
A P-value >0.05 implies that H0 is trueAs the P-value is calculated under the assumption H0 is true, a P-value above 0.05 merely implies that similar or more extreme data would be observed in >5% of similar future experiments.
A P-value <0.05 implies that H1 is trueSimilarly to the previous two misconceptions, a P-value below 0.05 only represents the <5% probability that similar or more extreme data would be observed in such future experiments.
A P-value <0.05 implies that there is an important difference between groupsSmaller P-values represent the probability of the observed data under the null hypothesis, which can particularly occur in very large trials, although a treatment effect may be very small.
A P-value >0.05 implies that there is no difference between groupsLarger P-values simply represent that the observed data are still not that unusual under the null hypothesis, which may be particularly evident in smaller trials.
MisconceptionAdequate interpretation
The P-value represents the probability of H0 being trueAs the P-value is calculated under the assumption that H0 is true, it cannot represent a probability of a hypothesis. Instead, it represents the probability of finding similar—or more extreme—data in future similar experiments, under the assumption that H0 is true.
The P-value represents the 1-probability of H1 being trueSimilarly, as the P-value is calculated under the assumption that H0 is true, it cannot simultaneously represent the probability that H1 is true.
A P-value >0.05 implies that H0 is trueAs the P-value is calculated under the assumption H0 is true, a P-value above 0.05 merely implies that similar or more extreme data would be observed in >5% of similar future experiments.
A P-value <0.05 implies that H1 is trueSimilarly to the previous two misconceptions, a P-value below 0.05 only represents the <5% probability that similar or more extreme data would be observed in such future experiments.
A P-value <0.05 implies that there is an important difference between groupsSmaller P-values represent the probability of the observed data under the null hypothesis, which can particularly occur in very large trials, although a treatment effect may be very small.
A P-value >0.05 implies that there is no difference between groupsLarger P-values simply represent that the observed data are still not that unusual under the null hypothesis, which may be particularly evident in smaller trials.

Partly based on Goodman et al. [5] and Greenland et al. [6].

H0: null hypothesis, H1: alternative hypothesis.

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