{ "background": "Evaluating the cost-effectiveness of community health centre systems in low-resource settings is methodologically challenging, with a paucity of robust field trial designs that account for complex operational and economic variables.", "purpose and objectives": "This case study aimed to methodologically evaluate the implementation of a randomised field trial designed to measure the cost-effectiveness of an integrated service delivery model within a Ghanaian community health centre system.", "methodology": "We conducted a pragmatic, cluster-randomised field trial across 24 centres. Cost data were collected via activity-based costing, and effectiveness was measured using disability-adjusted life years (DALYs) averted. Cost-effectiveness was analysed using a generalised linear mixed model: $\\text{ln}(\\text{Cost}{ij}) = \\beta0 + \\beta1 \\text{Treatment}j + \\gamma X{ij} + uj + \\epsilon{ij}$, where $uj$ represents cluster random effects. Robust standard errors were used for inference.", "findings": "The trial methodology proved feasible but identified significant operational constraints. The incremental cost-effectiveness ratio (ICER) point estimate favoured the intervention, but the 95% confidence interval was wide, ranging from £150 to £480 per DALY averted, indicating substantial uncertainty. A key theme was the high variability in resource utilisation between centres, which critically influenced the precision of economic estimates.", "conclusion": "The methodological evaluation underscores that while randomised designs are theoretically superior for economic evaluation in this context, their practical application requires substantial adaptation to local health system constraints to generate reliable estimates.", "recommendations": "Future cost-effectiveness trials in similar settings should incorporate longer lead-in periods for system readiness, employ adaptive sampling to manage heterogeneity, and embed prospective sensitivity analyses for key cost drivers.", "key words": "economic evaluation, health systems research, cluster randomised trial, sub-Saharan Africa, primary health care, implementation science", "contribution statement": "This paper provides a novel methodological framework and empirical