Evidence synthesis
Umbrella review
A review of systematic reviews, often used to map a broad evidence area.
What it means
Definition
Umbrella review. An umbrella review sits above individual systematic reviews and can compare the strength of evidence across related questions. It inherits limitations from the reviews and studies it includes.
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
An umbrella review can show that several claimed diet effects are supported only by low-certainty evidence.