Causal inference: Bradford Hill criteria: 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.

Try it

PSM · Causal inference: Bradford Hill criteria

Sample item

A researcher reviews evidence that a drug exposure causes a congenital anomaly. Among the Bradford Hill considerations, which is the only one that must always be satisfied for a causal claim?

ATemporality, with exposure preceding the outcomeBStrength of associationCAnalogy with similar exposuresDBiological gradient

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

The answer and the reasoning

A. Temporality, with exposure preceding the outcome

Temporality is the one absolute requirement: the cause must precede the effect. The other viewpoints, such as strength, consistency, dose-response, plausibility and analogy, add weight but are not individually mandatory. A weak association or a lack of a dose-response curve does not by itself exclude causation.

Option by option

A. Temporality, with exposure preceding the outcome (correct)
Correct. Without exposure preceding outcome, causation is impossible.
B. Strength of association
A weak association can still be causal, so strength is supportive but not essential.
C. Analogy with similar exposures
Analogy is the weakest of the criteria and is merely suggestive.
D. Biological gradient
Some causal relations have threshold effects without a graded dose-response.

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 A, Temporality, with exposure preceding the outcome. Temporality is the one absolute requirement: the cause must precede the effect.

Why is "Strength of association" not the answer?

A weak association can still be causal, so strength is supportive but not essential.

Why is "Analogy with similar exposures" not the answer?

Analogy is the weakest of the criteria and is merely suggestive.

Why is "Biological gradient" not the answer?

Some causal relations have threshold effects without a graded dose-response.

What concept does this question test?

It tests Causal inference: Bradford Hill criteria in PSM. The other viewpoints, such as strength, consistency, dose-response, plausibility and analogy, add weight but are not individually mandatory. A weak association or a lack of a dose-response curve does not by itself exclude causation.

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 Causal inference: Bradford Hill criteria?

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.