Question

What is NOT true about a case control study?

• A. It gives attributable risk
• B. It is less expensive
• C. It involves fewer subjects
• D. It provides quick results

Hint:

Case control studies work backward from disease to exposure and give an odds ratio, not incidence based measures like attributable risk.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks which statement is false about a case control study. In this design, researchers pick people who already have a disease (cases) and people who do not (controls), then look back in time to compare past exposure to a suspected cause.

Step 2: Key Formula or Approach:
A case control study starts from disease status, not exposure status, and it does not follow a defined population forward over time. Because of this, it cannot give the incidence of disease in exposed and unexposed people. Without incidence, absolute measures such as attributable risk and relative risk cannot be worked out directly. What a case control study can give is an odds ratio, which only estimates relative risk.

Step 3: Detailed Explanation:
Check each option against this rule.
"It gives attributable risk": this needs incidence data from a group followed over time, and a case control study never collects that. So this statement is false, and this is the option we want.
"It is less expensive": true. Since cases and controls are picked directly and there is no need to follow people up for years, the study costs less than a cohort study.
"It involves fewer subjects": true. Even a rare disease can supply enough cases from hospital records, and each case needs only one or a few matched controls, so the total sample stays small.
"It provides quick results": true. Because the disease outcome has already happened before the study starts, there is no waiting period, so results come out fast compared with a cohort study.

Step 4: Final Answer:
The one false statement is that a case control study gives attributable risk. It can only give an odds ratio as an estimate of relative risk, not attributable risk.