Community Mental Health Service Lay Counsellor Supervision Density and Suicide Risk Detection in Ugandan Primary Care: A Stepped-Wedge Cluster Estimation of Supervision Exposure

Lay counsellors increasingly carry suicide risk detection in Ugandan primary care, yet the supervision intensity required to sustain detection quality remains unquantified. the present analysis characterises the operating characteristics of a stepped-wedge cluster design for estimating the effect of supervision density on suicide risk detection, using a before-after-control-impact estimator under a declared variance structure (between-cluster SD = 6.0, residual SD = 4.5, intraclass correlation = 0.64). Power was estimated across 2000 replications per design cell for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points.54 clusters are required to detect a 5-percentage-point effect at 80% power, and that minimum detectable effects decline steeply as cluster counts rise from 8 to 32. The intraclass correlation of 0.64 dominates the design's sensitivity, compressing effective information and making supervision density a cluster-level rather than counsellor-level exposure.