**Question:** Sampling method used in assessing immunization status of children under immunization programme is

A. Random sampling
B. Stratified sampling
C. Convenience sampling
D. Cluster sampling

**Correct Answer:** **D. Cluster sampling**

**Core Concept:** Immunization programs aim to ensure equitable distribution of vaccines and monitor vaccination coverage among target populations. A variety of sampling methods are used to achieve this goal.

**Why the Correct Answer is Right:** Cluster sampling is a type of probability sampling technique where the sampling units (children) are grouped into clusters (e.g., villages, schools). By randomly selecting clusters, the sampling procedure allows for efficient and effective assessment of vaccination status among a representative sample of the target population.

**Why Each Wrong Option is Incorrect:**

A. Random sampling is a non-probability technique that selects participants at random without considering the clusters. This method may result in an unrepresentative sample and could lead to inaccurate assessment of immunization coverage.

B. Stratified sampling divides the population into strata (e.g., age groups) and then selects participants within each stratum. This method is suitable when the study focuses on stratified variables or when the population is heterogeneous, but in this case, it does not specifically address the need to assess the immunization status at the cluster level.

C. Convenience sampling selects participants based on their availability and ease of access. This method is not suitable for a population-based assessment of immunization coverage, leading to a non-representative sample and unreliable results.

**Clinical Pearl:** Immunization sampling methods should be chosen based on the research objective and population characteristics. Cluster sampling allows for efficient assessment of immunization coverage by considering the immunization status within clusters, ensuring a representative sample for programmatic decision-making and resource allocation.