Question
Which is not an analytical study:
| A. |
Case control study |
| B. |
Cohort study |
| C. |
Ecological studies |
| D. |
Field trials |
Show Answer
|
Correct Answer » A Explanation |
 |
Classification of Epidemiological Studies
1. Observational Studies
- Descriptive: Case report, Case series, Ecological study, Descriptive cross-sectional study
- Analytical: Case-control study, Cohort study, Analytical cross-sectional study
2. Experimental (Interventional) Studies
- Clinical trial
- Field trial
- Community trial
Field trials are experimental studies because the investigator assigns the intervention; therefore, they are not analytical studies.
Option-wise Explanation
A. Case-control study – Incorrect
- Analytical observational study.
- Starts with disease and looks back for exposure.
- Measures Odds Ratio (OR).
B. Cohort study – Incorrect
- Analytical observational study.
- Starts with exposure and follows participants over time.
- Measures Relative Risk (RR).
C. Ecological (Correlational) study – Incorrect
- Observational study conducted at the population level.
- Used to study exposure–disease associations.
- Prone to ecological fallacy.
D. Field trial – Correct
- Experimental (interventional) study.
- Conducted in healthy individuals to evaluate preventive interventions (e.g., vaccines).