Screening: 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 · Screening

Sample item

Lead-time bias in a screening programme makes survival appear:

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

The answer and the reasoning

C. Longer, even if the date of death is unchanged

Screening finds disease earlier, so survival measured from diagnosis looks longer even if death occurs at the same time. Randomised trials with mortality as the outcome avoid this bias.

Option by option

  • A. Shorter, even if treatment improves

    Lead time lengthens apparent survival; it does not shorten it.

  • B. Longer only in older patients

    It is not specific to older patients.

  • C. Longer, even if the date of death is unchanged (correct)

    Correct. The clock starts earlier but death does not move.

  • D. Unchanged in all cases

    It changes apparent survival whenever screening advances diagnosis.

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 C, Longer, even if the date of death is unchanged. Screening finds disease earlier, so survival measured from diagnosis looks longer even if death occurs at the same time.

Why is "Shorter, even if treatment improves" not the answer?

Lead time lengthens apparent survival; it does not shorten it.

Why is "Longer only in older patients" not the answer?

It is not specific to older patients.

Why is "Unchanged in all cases" not the answer?

It changes apparent survival whenever screening advances diagnosis.

What concept does this question test?

It tests Screening in PSM. Randomised trials with mortality as the outcome avoid this 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 Screening?

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.