Epidemiology: hierarchy of evidence: 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: hierarchy of evidence

Sample item

For a question about the effectiveness of a treatment, which of these sits highest in the usual hierarchy of evidence?

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

The answer and the reasoning

A. A systematic review of randomised trials

In the standard hierarchy, systematic reviews and meta-analyses of randomised trials give the strongest evidence for treatment effects. Cohort studies come below, followed by case-control studies and then case series and expert opinion. Design strength depends on control of bias and chance.

Option by option

  • A. A systematic review of randomised trials (correct)

    Correct. A synthesis of randomised trials ranks at the top for treatment questions.

  • B. A case-control study

    Case-control studies rank lower still because of recall and selection bias.

  • C. A committee of expert opinion

    Expert opinion ranks at the bottom of the hierarchy.

  • D. A well-conducted cohort study

    Cohort studies rank below randomised evidence because of confounding.

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, A systematic review of randomised trials. In the standard hierarchy, systematic reviews and meta-analyses of randomised trials give the strongest evidence for treatment effects.

Why is "A case-control study" not the answer?

Case-control studies rank lower still because of recall and selection bias.

Why is "A committee of expert opinion" not the answer?

Expert opinion ranks at the bottom of the hierarchy.

Why is "A well-conducted cohort study" not the answer?

Cohort studies rank below randomised evidence because of confounding.

What concept does this question test?

It tests Epidemiology: hierarchy of evidence in PSM. Cohort studies come below, followed by case-control studies and then case series and expert opinion. Design strength depends on control of bias and chance.

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: hierarchy of evidence?

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.