Epidemiology: Neyman bias: 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: Neyman bias

Sample item

A case-control study of acute myocardial infarction recruits cases from survivors admitted to a cardiac unit several months after the event. People who die soon after an infarct cannot be included, so a risk factor that makes the first attack rapidly fatal is under-represented among the cases. Which bias is this?

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

The answer and the reasoning

A. Neyman (prevalence-incidence) bias

Neyman bias arises when prevalent cases, surviving for some time, are studied instead of incident cases. Factors that cause early death or recovery are then missing among the cases, and the association with the exposure is distorted.

Option by option

  • A. Neyman (prevalence-incidence) bias (correct)

    Correct. Studying surviving prevalent cases instead of newly occurring cases causes Neyman bias.

  • B. Recall bias

    Recall bias arises when cases remember past exposures differently from controls, which the stem does not describe.

  • C. Lead-time bias

    Lead-time bias is the apparent lengthening of survival caused by earlier diagnosis in screening.

  • D. Berkson bias

    Berkson bias arises when hospital admission rates differ between exposed and unexposed people, not from loss of rapidly fatal cases.

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, Neyman (prevalence-incidence) bias. Neyman bias arises when prevalent cases, surviving for some time, are studied instead of incident cases.

Why is "Recall bias" not the answer?

Recall bias arises when cases remember past exposures differently from controls, which the stem does not describe.

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

Lead-time bias is the apparent lengthening of survival caused by earlier diagnosis in screening.

Why is "Berkson bias" not the answer?

Berkson bias arises when hospital admission rates differ between exposed and unexposed people, not from loss of rapidly fatal cases.

What concept does this question test?

It tests Epidemiology: Neyman bias in PSM. Factors that cause early death or recovery are then missing among the cases, and the association with the exposure is distorted.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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: Neyman bias?

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.