Urban development-induced digitization of customary land secretariat records and informal lineage mediation in Kumasi peri-urban areas: a difference-in-differences estimation of registry-integration exposure

Evaluations of customary land secretariat digitisation in Kumasi peri-urban areas routinely propose difference-in-differences designs that compare lineage mediation outcomes across exposed and unexposed stool lands, yet the statistical operating characteristics of those designs have not been characterised. 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. The analysis indicates that 54 clusters are required to detect a 5 percentage point effect at 80 per cent power, and that the minimum detectable effect falls steeply as cluster counts rise from 8 to 32. The results imply that the small-cluster designs common in peri-urban stool-land evaluations are underpowered for the effect sizes that registry-integration exposure plausibly generates, and that the field should treat cluster counts as a substantive design decision rather than an administrative afterthought.