Odds ratio

An odds ratio compares the odds of an outcome in one group with the odds in another. It's a way to measure how strongly two things are linked.

This term is specific to research interpretation and is defined on AnxietyResearch. Shrinktionary, the network's language layer, doesn't currently carry a canonical entry for it.

Odds aren't the same as risk. Risk is the chance something happens. Odds are the chance it happens divided by the chance it doesn't. An odds ratio of 1 means no difference between the groups. Above 1 means the outcome is more likely in the first group. Below 1 means it is less likely. Odds ratios appear most often in case-control studies.

Odds ratios show up when researchers study what is linked to anxiety, such as family history, sleep problems, or chronic illness. An odds ratio gives the direction and rough strength of a link. It doesn't prove that one thing caused the other.

A study reports that people with chronic pain have an odds ratio of 2.0 for also having an anxiety disorder. The odds of anxiety are about twice as high in the chronic pain group.

When an outcome is common, an odds ratio can look larger than the real difference in risk. A reader can easily mistake an odds ratio of 2.0 for "twice the risk," which isn't quite what it means. An odds ratio always needs a confidence interval to show how precise it is.