Sample size and sampling technique for clusters, households and individuals across four study arms of the TTLT model study, Tigrai, Ethiopia, 2020–2024
| Entity | Sample size included for trial | Sampling technique |
| Region | 1 region with a total of 7 zones | Purposely |
| Strata | 7 zones from a total of 746 possible clusters (kebeles) | Stratified sampling technique |
| Clusters per zone | 40 clusters in total to be selected proportional to their size | Simple random sampling |
| Clusters per study arm | Total clusters included for trial divided by 4 (number of study arms), n=10 clusters per study arm | Random assignment |
| Households per cluster | Total number of households divided by 4 (number of study arms) divided by 10 clusters, n=136 households per cluster | Systematic random sampling |
| Individuals per household | One person per household | Simple random sampling |