The number of pair-matched clusters required for this study was determined using a formula suggested by RJ Hayes and S Bennett [26] for a pair-matched cluster randomized trials of unequal cluster size as shown below. The sample size was calculated based on the following assumptions: an estimated average annual pulmonary TB case detection rate (CDR) of 40% in the study prisons (estimated using unpublished review of the two years DOTs record from some study prisons), expecting to detect a 50% increment in case detection rate over the intervention period (from 40% in the control groups to 60% in the intervention groups), a power of 80%, a coefficient of variation of 0.25, and a significance level of 0.05. The number of clusters was fixed considering only the primary outcome (case detection rate). A coefficient of variation of 0.25 was considered since there was no full data for the matched prison pairs to calculate the exact value.