What’s the Risk: Differentiating Risk Ratios, Odds Ratios, and Hazard Ratios?

The relative merits of risk ratios and odds ratios.

When a study outcome is rare in all strata used for an analysis, the odds ratio estimate of causal effects will approximate the risk ratio; therefore, odds ratios from most case-control studies can be interpreted as risk ratios. However, if a study outcome is common, the odds ratio will be further from 1 than the risk ratio. There is debate regarding the merits of risk ratios compared with odds...

Risk ratios and odds ratios--what are they?

A risk ratio (sometimes called relative risk, both abbreviated to RR) and an odds ratio (OR) are ways of expressing a comparison between two proportions. For example, in this paper, there are two randomised groups in the trial, women in the lateral position and women in the supported sitting position in the passive second stage of labour. The authors wanted to compare the proportions of instrum...

Relative Risk and Odds Ratios Examples

Risk Ratios

In human genetics and genetic epidemiology, risk ratios can assume a number of different forms, including risk ratios for relatives, for candidate genes, and for genetic markers. The goal of many genetic studies is to quantify the risk of disease occurrence associated with particular genetic factors. The strength of this association can depend on interactions between environmental and genetic f...

Instrumental variable estimation of causal risk ratios and causal odds ratios in Mendelian randomization analyses.

In this paper, the authors describe different instrumental variable (IV) estimators of causal risk ratios and odds ratios with particular attention to methods that can handle continuously measured exposures. The authors present this discussion in the context of a Mendelian randomization analysis of the effect of body mass index (BMI; weight (kg)/height (m)(2)) on the risk of asthma at age 7 yea...