Evidence quality

Mechanism

A proposed biological explanation for how something might work.

What it means

Definition

Mechanism: A mechanism can make a claim plausible, but plausibility is not the same as proof that an intervention improves outcomes in people.

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 nutrient may affect a pathway in cells, but that does not prove taking it prevents dementia.