An odds ratio compares the odds of an outcome in one group to the odds in another group
An odds ratio of 1 means no difference in odds between the groups
An odds ratio greater than 1 means higher odds of the outcome in the first group
An odds ratio less than 1 means lower odds of the outcome in the first group
An odds ratio of 2 means the odds are twice as high in the first group
An odds ratio of 0.5 means the odds are half as high in the first group
An odds ratio is not the same as risk ratio or probability
For rare outcomes, odds ratio and risk ratio may be similar
A confidence interval that includes 1 usually indicates no statistically significant association
The direction of interpretation depends on which group is used as the reference group