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

A case-control study uses hospitalised patients as both cases and controls and finds a spurious association between two conditions. Which bias is the likely explanation?

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

The answer and the reasoning

A. Berkson's (admission rate) bias

Berkson's bias arises in hospital-based studies when the probability of admission differs by exposure or disease, so hospital cases and controls differ systematically from the general population. It is a form of selection bias.

Option by option

  • A. Berkson's (admission rate) bias (correct)

    Correct. Differential admission to hospital distorts the comparison.

  • B. Observer bias

    Observer bias results from differences in how outcomes are measured.

  • C. Recall bias

    Recall bias arises from differences in remembering past exposure.

  • D. Lead-time bias

    Lead-time bias belongs to screening and survival comparison.

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 A, Berkson's (admission rate) bias. Berkson's bias arises in hospital-based studies when the probability of admission differs by exposure or disease, so hospital cases and controls differ systematically from the general population.

Why is "Observer bias" not the answer?

Observer bias results from differences in how outcomes are measured.

Why is "Recall bias" not the answer?

Recall bias arises from differences in remembering past exposure.

Why is "Lead-time bias" not the answer?

Lead-time bias belongs to screening and survival comparison.

What concept does this question test?

It tests Epidemiology in PSM. It is a form of selection bias.

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.