Evidence quality
Heterogeneity
Variation between studies, participants, interventions, or results.
What it means
Definition
Heterogeneity: Heterogeneity matters because pooled results may hide important differences. High heterogeneity makes simple summary claims less reliable.
What it can tell you
It can help clarify what sort of evidence or claim is being discussed.
What it cannot tell you
It cannot, by itself, prove that the headline is accurate or clinically important.
Headline trap
Why this matters in headlines
A meta-analysis of very different diets, populations, and outcomes may be hard to interpret.