All are advantages of Case control studies except:-

- Relative risk is calculated in coho study . Hence, option-2 is answer Case Control Studies Coho Studies 1. Proceeds from "effect to cause". Proceeds from "cause to effect" 2. Tests whether the suspected cause occurs more frequently in those with the disease than among those without the disease. Test whether disease occurs more frequently in those exposed, than in those not similarly exposed. 3. Usually the first approach to the testing of a hypothesis, but also useful for exploratory studies. Reserved for testing of precisely formulated hypothesis 4. Involves fewer number of subjects. Involves larger number of subjects. 5. Yields relatively quick results. Long follow-up period often needed, involving delayed results. 6. Suitable for the study of rare diseases. Inappropriate when the disease or exposure under investigation is rare 7. Generally yields only estimate of relative risk by odds ratio Yields incidence rates , RR as well as AR 8. Cannot yield information about disease other than that selected for study. Can yield information about more than one disease outcome. 9. Relatively inexpensive. Expensive.