In a research study, the odds of some outcome is the number of times it happened over the number
of times it didn’t happen (e.g. the number of people who had heart attacks over the number who didn’t)
An odds ratio is the ratio of two odds: the odds of the outcome of interest in the
experimental group divided by the odds in a control or baseline group.
An odds ratio greater than 1 means the outcome of interest (heart attacks or cancer diagnoses) was
more common in the experimental group (usually the group exposed to the risk factor), and an OR
below 1 means it was less common.
Where do I find it?Odds ratios will normally be reported in the abstract of a paper and/or in the results section.
They generally look like this: “OR 3.6” or sometimes “aOR 3.6”. Often, several ORs will be reported for different comparisons. For RealRisk, pick the OR most worth reporting.
For more on odds ratios:Check out our Youtube explainer.
