WHO recommended Sampling method for Immunisation coverage evaluation
Cluster random sampling (CRS) Applicable when units of population are natural groups or clusters. Use of CRS in India: Evaluation of immunization coverage. WHO technique used in CRS: 30 x 7 technique (total = 210 children) 30 clusters, each containing 7 children who are 12 - 23 months age and are completely immunized for primary immunization (till Measles vaccine). Accuracy: Low error rate of only +- 5%. Limitation: Clusters cannot be compared with each other.
Simple random sampling
Cluster random sampling
Stratified random sampling
Convenience sampling
Biostats