Question

The unit of study in an ecological study is?

• A. Population
• B. Patient
• C. Community
• D. Case

Hint:

Ecological studies correlate at group level - the unit is the population.

Answer 1

The Correct Option is A

Step 1: Define the study design. An ecological (correlational) study compares groups rather than individuals. In ecological studies the unit of observation is the population or community, so the answer is population, option (a).
Step 2: How it works. Disease rates and exposures are measured in a series of populations and the relationship between exposure and disease is examined at the group level.
Step 3: Source of data. The information on disease and exposure is often abstracted from published aggregate statistics rather than collected from individuals.
Step 4: Why the close distractor is wrong. Although community appears similar, the standard teaching point names the population as the unit of analysis; patient and case refer to individual-level units used in cohort or case-control designs, not ecological studies.