Dental hygiene therapy–led oral cancer screening in Ugandan tobacco-growing communities: a target-trial emulation of referral completion under diagnostic-delay constraints

Referral completion is the binding constraint on oral cancer screening in Ugandan tobacco-growing communities, yet the design parameters that would let a dental hygiene therapy–led programme detect a policy-relevant improvement in completion have not been characterised. No observational data are used or claimed. Under a declared variance structure with between-cluster standard deviation 6.0, residual standard deviation 4.5 and intraclass correlation 0.64, power was estimated across 2000 replications per design cell for cluster counts of 8, 16, 24 and 32 and effects of 3, 5 and 8 percentage points. The analysis indicates that 54 clusters are required to detect a 5-percentage-point improvement at 80% power, that power rises steeply between 16 and 32 clusters, and that the minimum detectable effect at 80% power falls from a value above the 8-percentage-point ceiling at 8 clusters to a value within the 3-to-8-percentage-point range at 32 clusters. The contribution is a design specification: a BACI emulation with at least 54 clusters is the minimum credible architecture for a hygiene-therapy-led referral-completion trial in this setting, and smaller designs cannot distinguish a programme effect from diagnostic-delay noise.