Following are true about case control study except-
Case control studies often retrospective studies are common first approach to test causal hypothesis. In recent years, case control study has emerged as a permanent method of epidemiological investigation. Both exposure and outcome has occurred before the study. Study proceeds backwards from effect to cause. It uses a control or comparison group to suppo or refute an inference Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 79
Retrospective study
Risk factor is present but not outcome
Both outcome and risk factors have occured
There is not risk to people in study
Epidemiology