A researcher collects historical data on a group of subjects and follows them to determine the occurrence of a disease or outcome. Which type of study design does this describe?

1. A

   Prospective cohort study

2. B

   Retrospective (historical) cohort study

3. C

   Case-control study

4. D

   Cross-sectional study

Appeared in: NORCET 9 Mains - 2025

Explanation

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• A retrospective cohort study uses historical data to define a cohort based on past exposure.
• The researcher then traces these individuals forward in time using existing records to identify outcomes that have already occurred.
• The key feature is that both the exposure and the outcome happened in the past, before the study was initiated.
• This design is efficient for studying diseases with long latency periods and is less costly and time-consuming than a prospective study.

Why Other Options Were Wrong

• Option A: A prospective cohort study starts in the present and follows subjects into the future to observe outcomes that have not yet occurred. The question specifies using 'historical data' for follow-up, indicating past events.
• Option C: A case-control study starts with the outcome (disease) and looks backward in time to find the exposure. The question describes starting with exposure (via historical data) and looking forward for the outcome.
• Option D: A cross-sectional study measures exposure and outcome at a single point in time, like a snapshot. It does not involve 'following' subjects over any period.

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Clinical Relevance

• Nursing practice connection: Knowing Epidemiological Study Designs helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
• Understanding different study designs is fundamental for evidence-based nursing practice. It allows nurses to critically appraise research articles and determine the strength of the evidence.
• Nurses can better evaluate the validity of conclusions about risk factors and disease, which informs patient education and health promotion strategies.
• What if? If the researcher identified a group today based on their current exposure status and planned to contact them every year for the next 10 years, the design would change to a prospective cohort study, which is stronger for establishing causality but more expensive and time-consuming.

How to Approach the Question

• First, identify the key temporal elements in the question stem: 'collects historical data' and 'follows them to determine the occurrence of a disease'.
• Analyze the starting point: 'Historical data' means the study begins by looking at events that already happened in the past.
• Analyze the direction of inquiry: 'Follows them' from a past point to an outcome indicates a forward direction from exposure to outcome.
• Combine these two points: The study looks at past events and moves forward in time from exposure to outcome. This defines a retrospective cohort study.
• Compare this with the definitions of the other options to confirm your choice. A prospective study moves forward from the present, a case-control study moves backward from the outcome, and a cross-sectional study is a snapshot in time.

Concept Tested & Keywords

• Concept Tested: Epidemiological Study Designs
• Stem keywords: historical data, follows them, occurrence of a disease, study design
• Lead-in keywords: Which type of study
• Negative lead-in flag: false

Question ID

QFO7h8cUXBQM0OXOvyqAHc

Copy ID

Reference Book

E6 NursingResearch Suresh Sharma 5e Part 1 p. 183-185