Table 3

The analogy between diagnostic tests and clinical trials.

Diagnostic testing

Clinical trials

Absence of disease

Truth of null hypothesis

Presence of disease

Falsity of null hypothesis

Cutoff between positive and negative results

Significance level, α

Test result


Negative result

P-value > α

Positive result

P-value < α



False positive rate (1-specificity)

Significance level, α

Prior probability of disease

Prior probability of a difference between groups

Posterior probability of disease, given test result

Posterior probability of a difference between groups, given study results

Westover et al. BMC Medicine 2011 9:20   doi:10.1186/1741-7015-9-20

Open Data