Table 1.

Information on intracluster correlation coefficient from previous studies

Data source, level of clustering and sample	Intracluster correlation	Average cluster size	Design effect
National level data sets
Comprehensive National Nutrition Survey,2 Clustering at PSU level Children and adolescents: 1–19 years	1–4 years: 0.113 5–9 years: 0.113 10–19 years: 0.091	10 per age group	1–4 years: 2.28 5–9 years: 2.24 10–19 years: 2.20
National Nutrition Monitoring Bureau, 201217(Telangana and Andhra Pradesh data), Clustering at village level Children under 5 years and their mothers	0.117	38	5.3
Previous published studies
Shet et al 18 c-RCT in 12–59 months children, Clustering at village level	0.05	25	2.2
Bharti et al 19 c-RCT in rural women and adolescent girls, Clustering at village level	0.027	33	1.92
Unpublished data from other studies by investigators
Andhra Pradesh Children and Parents Study data: household members: Household members from 29 villages, age range 5–50 years, Clustering at village level	ICC: 0.016	185	4.036

c-RCT, cluster randomised controlled trial; ICC, intracluster correlation; PSU, Primary Sampling Unit.