Question

A new community intervention is initiated to reduce prenatal sepsis. Researchers allocated 20 PHCs to receive standard care and 20 PHCs to receive a community-based intervention. What type of study design is this?

• A. Cross-sectional study
• B. Case-control study
• C. Quasi-experimental study
• D. Cluster-randomized control trial

Hint:

If groups like schools, villages or PHCs are randomized instead of individuals, it is a cluster-randomized trial.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The study describes an experimental intervention with an allocated control group. The key detail is that the unit of allocation/randomization is not the individual patient, but a whole Primary Health Center (PHC).
Step 2: Detailed Explanation:

Definition of Cluster RCT: This is a type of randomized controlled trial where pre-existing groups or "clusters" of people (such as hospitals, clinics, schools, or villages) are randomly assigned to either the intervention or the control group.

Why use Cluster Randomization?

Prevention of Contamination: If individuals in the same clinic were randomized differently, those in the control group might learn about and adopt the intervention from their neighbors, ruining the study's validity.

Logistical Practicality: Many community interventions are easier to implement at the institutional or organizational level.


Applying to the scenario:

The unit of allocation is the PHC (a cluster).

There are 40 total units divided equally (20 and 20).

This perfectly matches the definition of a Cluster-Randomized Control Trial (C-RCT).


Other options:

Quasi-experimental: An intervention study that lacks randomization. Formal allocation of 20 vs 20 suggests randomization was used.

Case-control: An observational study looking retrospectively at outcomes.


Step 3: Final Answer:
Because the study randomizes based on groups (clusters) of people rather than individuals, it is a cluster-randomized control trial.