Evidence-appraisal glossary

Posterior probability

In Bayesian analysis, the posterior probability is the updated probability of a hypothesis or parameter after the prior has been combined with the observed data.

Also called: posterior.

It is the main output of a Bayesian analysis and can be read directly as the probability of the hypothesis given the data, which is what a credible interval summarizes. Two studies starting from different priors can reach different posteriors from the same data, so understanding a posterior means knowing which prior produced it.

This is a plain-language methodology definition for reading research. It is general education, not medical advice.

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