Statistics and risk
Odds ratio
A comparison of odds between groups, often used in case-control studies and logistic regression.
What it means
Definition
Odds ratio. An odds ratio compares odds rather than direct probabilities. When an outcome is uncommon, it can look similar to a risk ratio; when an outcome is common, it can appear more dramatic than the actual risk difference.
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 headline may treat an odds ratio as a direct risk increase, which can overstate the meaning of the finding.