Evidence synthesis
Meta-analysis
A statistical synthesis combining results from multiple studies.
What it means
Definition
Meta-analysis. Meta-analysis can improve precision by pooling data, but pooling does not remove bias from poor studies. Heterogeneity, publication bias and study quality need careful interpretation.
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 pooled estimate may look precise while combining studies that asked meaningfully different questions.