True about case control study
A. Helpful for evaluation of rare diseasesB. Expensive
C. Incidence can be measured
D. Rare causes studied
E. Selection bias common
The Answer is . (A) Helpful for evaluation of rare
diseases: (E) Selection bias common
Advantages of case control study that it is
— Rapid and inexpensive
— particularly suitable to investigate rare diseases
or diseases about which little is known.
— require relatively few subjects, with no risk to
them
— study of several different aetiological factors
Risk Factors can be identified - attrition problem,
ethical problem minimal
Disadvantages
• Problem of bias e.g. selection, Berkesonian,
interview etc
• Can not measure incidence, can only extimate relative
risk
• Don’t distinguish between cause and associated
factors
• Not suited for evaluation of therapy or prophylais
of disease
