Final answer:
Odds ratios have the advantage of being used in case-control studies where relative risk cannot be directly calculated. They are suitable for evaluating rare outcomes and retrospective study designs, providing an alternative method to relative risk for inferring associations in such cases.
Step-by-step explanation:
Odds ratios are interpreted in a way that is similar to the relative risk, but have the advantage of being applicable to case-control studies where relative risk cannot be directly calculated. This is because odds ratios can be used when the outcome of interest is rare or when the study design is retrospective, in contrast to relative risk which is typically used in prospective cohort studies. Hence, when calculating the association between exposure to a risk factor and the outcome in a case-control study, odds ratios are a more suitable measure.
To calculate odds ratios, we use a 2 x 2 table but instead of dividing the incidence in the exposed group by the incidence in the unexposed group, the ratio of odds in the exposed group is compared to the odds in the unexposed group. Since incidences cannot be directly known from a case-control study, the odds ratio provides an alternative method to infer the strength of the association between the exposure and the outcome.