Limitation of Risk Ratio
1. Sensitivity to Outcome Frequency: The risk ratio is sensitive because small changes in the number of cases can lead to large fluctuations in the risk ratio. this makes the interpretation challenging, especially in small studies.
2. Inability to Establish Causality: The risk ratio quantifies the relation between the exposure and the outcome but it does not establish the possible causalities. Therefore, the researchers need to be careful while concluding the causal relationships based solely on the risk ratio.
3. Limited General Applicability: The risk ratio obtained from a particular study may not be valid to other populations. Differences in population, exposure levels, or other factors may affect the extent and direction of the risk ratio.
4. Time-to-Event Data: Risk ratios are used to compare the incidence of outcomes between groups at a single point in time. However, they may not be suitable for analyzing time-to-event data where the outcome occurs over some time. In this case, alternative measures become more suitable.
5. Inaccuracy in Rare Outcomes: The risk ratio during certain circumstances may overestimate or underestimate the true risk difference between exposed and unexposed groups which will lead to vague estimates.