Purposeful sampling is appropriate for qualitative data collection, such as focus group discussions or semistructured interviews. Purposeful, also known as nonrandom, sampling is the selection of participants based on their knowledge, perspective or other characteristics of interest (e.g., females or males, young or old, very poor or better off). ...
Clustering your sample
If you cluster your sample, first determine the number of clusters you will select. The number of clusters (e.g., communities, villages, administrative units, groups) should be decided based on the variability between clusters and the variability within clusters. Aim to capture the greatest degree of variability within your sample. If...
standard sampling equation to determine a sample size
Use the standard sampling equation to determine a sample size sufficient for generalizing results to represent the target population In determining an appropriate sample size (i.e., the number of units to be surveyed), consider the sampling methodology (i.e., how sampling units, such as households, will be selected) and the analysis...