Odds ratio

Odds ("odds" can be translated as "chances" or "odds ratio" as "relative chances") are a way of indicating probabilities in statistics. Odds are calculated as quotients of the probability that an event will occur and the probability that it will not occur. Basically, a value of odds of 1.0 expresses a ratio of 50:50, values > 1 mean that the category in the numerator is < 1, the category in the denominator > 1. The odds ratio is used in statistics to evaluate the difference of 2 odds and thus make statements about the strength of relationships. An OR = 1 means that there is no difference in the odds. If OR > 1, the odds of the first group are larger; if OR < 1, they are smaller than those of the second group.