Study design: 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 · Study design

Sample item

Which study design is most efficient for investigating a rare disease?

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

The answer and the reasoning

B. Case-control study

Case-control studies begin with people who have the outcome and compare prior exposures, making them efficient when the disease is rare.

Option by option

  • A. Cross-sectional survey of only healthy people

    Healthy-only surveys cannot compare disease occurrence.

  • B. Case-control study (correct)

    Correct: selecting cases first avoids following a huge population for rare events.

  • C. Randomized trial enrolling the whole population

    Whole-population trials are usually impractical for rare outcomes.

  • D. Ecological study with no individual data

    Ecological data cannot establish individual exposure relationships reliably.

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 B, Case-control study. Case-control studies begin with people who have the outcome and compare prior exposures, making them efficient when the disease is rare.

Why is "Cross-sectional survey of only healthy people" not the answer?

Healthy-only surveys cannot compare disease occurrence.

Why is "Randomized trial enrolling the whole population" not the answer?

Whole-population trials are usually impractical for rare outcomes.

Why is "Ecological study with no individual data" not the answer?

Ecological data cannot establish individual exposure relationships reliably.

What concept does this question test?

It tests Study design in PSM. The correct option holds because: Correct: selecting cases first avoids following a huge population for rare events.

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 Study design?

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.