Table 1

Sample size and sampling technique for clusters, households and individuals across four study arms of the TTLT model study, Tigrai, Ethiopia, 2020–2024

EntitySample size included for trialSampling technique
Region1 region with a total of 7 zonesPurposely
Strata7 zones from a total of 746 possible clusters (kebeles)Stratified sampling technique
Clusters per zone40 clusters in total to be selected proportional to their sizeSimple random sampling
Clusters per study armTotal clusters included for trial divided by 4 (number of study arms), n=10 clusters per study armRandom assignment
Households per clusterTotal number of households divided by 4 (number of study arms) divided by 10 clusters, n=136 households per clusterSystematic random sampling
Individuals per householdOne person per householdSimple random sampling