Mortality Effects of Performance-Based Financing Removal in Tanzania: A Target-Trial Emulation Across District Health Systems

Performance-based financing (PBF) was introduced across Tanzanian district health systems and later withdrawn in several districts, leaving unresolved whether removal altered mortality. Because randomised evidence on PBF withdrawal is unavailable, the present analysis characterises the operating characteristics of a target-trial emulation that treats removal as a before-after-control-impact (BACI) design. The analysis is a replication-based evaluation of the before-after-control-impact estimator under a declared variance structure (between-cluster SD = 6.0, residual SD = 4.5, intraclass correlation = 0.640). Power was estimated across 2000 design cells spanning 8, 16, 24 and 32 clusters and effects of 3, 5 and 8 percentage points. The design required 54 clusters to detect a 5-percentage-point mortality difference at 80% power. Estimated power rose with cluster count and effect size, and the minimum detectable effect at 80% power fell as clusters increased. The intraclass correlation of 0.64 dominated the variance budget and made small cluster counts unreliable. Target-trial emulation of PBF removal is feasible only when the cluster count is adequate to the intraclass correlation, and it specifies the design conditions under which a district-level mortality effect of removal can be distinguished from secular change.