Epidemiology: practice question

A PSM question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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PSM · Epidemiology

Sample item

In which study design is the odds ratio the appropriate measure of association?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Case-control study

Case-control studies sample by outcome, so incidence cannot be calculated and the odds ratio estimates the relative risk when the disease is rare. Cohort studies and trials give relative risk directly.

Option by option

  • A. Ecological study

    Ecological studies compare group-level data and cannot give individual odds ratios.

  • B. Randomised controlled trial

    Trials yield relative risk and risk difference.

  • C. Cohort study

    Cohort studies yield relative risk because exposed and unexposed groups are followed.

  • D. Case-control study (correct)

    Correct. Sampling by disease status allows odds but not incidence.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is D, Case-control study. Case-control studies sample by outcome, so incidence cannot be calculated and the odds ratio estimates the relative risk when the disease is rare.

Why is "Ecological study" not the answer?

Ecological studies compare group-level data and cannot give individual odds ratios.

Why is "Randomised controlled trial" not the answer?

Trials yield relative risk and risk difference.

Why is "Cohort study" not the answer?

Cohort studies yield relative risk because exposed and unexposed groups are followed.

What concept does this question test?

It tests Epidemiology in PSM. Cohort studies and trials give relative risk directly.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Epidemiology?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.