A prevalence ratio, or ; A smaller proportion of the probiotic group developed diarrhoea associated with antibiotic use compared with the placebo group (7 (12%) v 19 (34%);The relative risk is best estimated using a population sample, but if the rare disease assumption holds, the odds ratio is a good approximation to the relative risk — the odds is p / (1 − p), so when p moves towards zero, 1 − p moves towards 1, meaning that the odds approaches the risk, and the odds ratio approaches the relative risk
Table 1 From Relationships Among Three Popular Measures Of Differential Risks Relative Risk Risk Difference And Odds Ratio Semantic Scholar
