1. Average cluster size and design effect of cluster‐randomised trials.

Study	Original sample size		Number of clusters	Average cluster size	Intracluster correlation coefficient	Design effect
	Intervention	Control
Muhoozi 2018	243	224	10	47	0.05	3.3
Bhandari 2004	552	473	8	128	0.05	7.4
Ferreira 2019	317	300	20	31	0.05	2.5
Morandi 2019	295	267	22	26	0.05	2.2
Nair 2017	1541	1460	120	25	0.05	2.2
Nikiema 2017	1083	1170	12	188	0.05	10.3
Penny 2005	187	190	12	31	0.05	2.5
Rafieya‐Kopaei 2019	60	30	6	15	0.05	1.7
Roy 2007	306	305	121	5	0.05	1.2
Saleem 2014	118	94	10	21	0.05	2.0
Shi 2009	294	305	8	75	0.05	4.7
Vazir 2013	210	202	60	7	0.05	1.3