Use of odds ratio questioned.

Odds Ratio, Hazard Ratio and Relative Risk

Odds ratio (OR) is a statistic commonly encountered in professional or scientific medical literature. Most readers perceive it as relative risk (RR), although most of them do not know why that would be true. But since such perception is mostly correct, there is nothing (or almost nothing) wrong with that. It is nevertheless useful to be reminded now and then what is the relation between the rel...

Prevalence odds ratio v prevalence ratio.

Statistics notes. The odds ratio.

In recent years odds ratios have become widely used in medical reports—almost certainly some will appear in today’s BMJ. There are three reasons for this. Firstly, they provide an estimate (with confidence interval) for the relationship between two binary (“yes or no”) variables. Secondly, they enable us to examine the effects of other variables on that relationship, using logistic regression. ...

The odds ratio: impact of study design.

In the previous column 1 we considered the “two-by-two” contingency table, a simple square array used to provide a tabular display of the relationship between two categorical variables, each having only two levels. Figure 1 shows such a table, where the rows correspond to nutritional status and the columns correspond to disease status. We showed that the relationship between the two variables c...

To use or not to use the odds ratio in epidemiologic studies

This paper argues that the use of the odds ratio parameter in epidemiology needs to be considered with a view to the specific study design and the types of exposure and disease data at hand. Frequently, the odds ratio measure is being used instead of the risk ratio or the incidenceproportion ratio in cohort studies or as an estimate for the incidence density ratio in case-referent studies. Ther...