Evidence-appraisal glossary
Secondary endpoint
A secondary endpoint is an additional outcome a trial measures beyond its primary one, used to describe further effects but not usually the basis for the trial's main conclusion.
Also called: secondary outcome.
Secondary endpoints can capture side benefits, harms, or quality-of-life effects that round out the picture of a treatment. Because a trial tests many of them, some will look significant by chance unless the analysis accounts for that multiplicity, so a positive secondary result is usually best read as hypothesis-generating rather than proof. The exception is when a trial pre-specifies a hierarchical testing order that controls the error rate, which lets a ranked secondary endpoint carry confirmatory weight.
Read the full Reading the Evidence blog.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.