Epidemiology: censoring in survival analysis: 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: censoring in survival analysis

Sample item

In a Kaplan-Meier analysis of a cancer drug, one patient moves abroad at month 14 with no information about his later status. How should he be handled?

AExcluded entirely from the analysisBCounted as dead at 14 monthsCCounted as alive until the end of the studyDCensored at 14 months, contributing follow-up until then

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

The answer and the reasoning

D. Censored at 14 months, contributing follow-up until then

A patient lost to follow-up is censored: his time at risk up to the last contact is used, and nothing is assumed after it. Counting him dead or alive would bias survival downwards or upwards. Censoring lets incomplete follow-up still contribute information.

Option by option

A. Excluded entirely from the analysis
Complete exclusion wastes information and can bias results.
B. Counted as dead at 14 months
Counting him as dead would underestimate survival.
C. Counted as alive until the end of the study
Counting him alive to the end overestimates survival.
D. Censored at 14 months, contributing follow-up until then (correct)
Correct. Censoring uses the information available until he was lost.

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.

Questions about this PSM question

What is the answer to this PSM question?

The best answer is D, Censored at 14 months, contributing follow-up until then. A patient lost to follow-up is censored: his time at risk up to the last contact is used, and nothing is assumed after it.

Why is "Excluded entirely from the analysis" not the answer?

Complete exclusion wastes information and can bias results.

Why is "Counted as dead at 14 months" not the answer?

Counting him as dead would underestimate survival.

Why is "Counted as alive until the end of the study" not the answer?

Counting him alive to the end overestimates survival.

What concept does this question test?

It tests Epidemiology: censoring in survival analysis in PSM. Counting him dead or alive would bias survival downwards or upwards. Censoring lets incomplete follow-up still contribute information.

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: censoring in survival analysis?

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.