Evidence quality
Confounder
A third factor that can distort the apparent relationship between an exposure and an outcome.
What it means
Definition
Confounder. A confounder is linked to both the exposure and the outcome, making an association look causal when it may not be. Observational studies try to adjust for confounders, but residual confounding often remains possible.
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
If coffee drinkers exercise more, exercise could partly explain lower disease rates attributed to coffee.