← Back to Glossary

Odds Ratio

Odds ratio is the odds of an outcome relative to the odds of the opposite outcome.

Definition

Odds ratio is the ratio of odds. In the probability conversion context, it often refers to odds p divided by (1 minus p). In evidence contexts, an odds ratio can describe how evidence shifts odds.

Why it matters

Odds ratio is a bridge between probability language and multiplicative updates. It pairs naturally with log odds and Bayes updates.

Common pitfalls

Confusing odds ratio with likelihood ratio: Likelihood ratio measures evidence strength, not baseline odds.