What is the odds ratio?

An odds ratio (OR) is a measure of the strength of association between an exposure and an outcome used in cross-sectional and retrospective studies (case-control). The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure. 

is a statstical measure of association between an exposure and an outcome used commonly in clinical research and epidemoilogy

An odds ratio (OR) is a measure of association between an exposure and an outcome