All are disadvantages of Coho study except: (A) Coho study involve a large number of people, (B) Coho studies are expensive, (C) Recall bias, (D) Attrition
Answer is C. Disadvantages of coho study Time consuming and Expensive Attrition - loss of follow up Hawthorne bias Ethical issues Not useful in rare disease Disadvantages of case control study Calculation of Odds ratio (Relative risk - more accurate than OR) Recall bias