{ "background": "Community health centres are a cornerstone of primary healthcare delivery in many sub-Saharan African nations, yet robust evidence on their cost-effectiveness remains limited. This gap hinders optimal resource allocation and health system strengthening.", "purpose and objectives": "This protocol details a randomised field trial to evaluate the cost-effectiveness of two distinct community health centre system models in Senegal. The primary objective is to estimate the incremental cost-effectiveness ratio (ICER) of an enhanced service delivery model compared to the standard model, measured in cost per disability-adjusted life year (DALY) averted.", "methodology": "A three-arm, cluster-randomised controlled trial will be conducted across 60 rural communities. Clusters will be randomly allocated to: a standard model (control), an enhanced model with additional preventative services, or an enhanced model with improved diagnostic capacity. Cost data will be collected from a health system perspective. Effectiveness will be measured via household surveys capturing morbidity and mortality. The primary analysis will use a generalised linear mixed model: $\\log(E[Y{ij}]) = \\beta0 + \\beta1 T{1ij} + \\beta2 T{2ij} + \\gamma X{ij} + uj$, where $Y{ij}$ is the DALY outcome for individual $i$ in cluster $j$, $T$ denotes treatment arms, $X$ are covariates, and $uj$ is a cluster random effect. Uncertainty will be characterised using 95% confidence intervals derived from bootstrapping.", "findings": "As a protocol, no empirical findings are presented. The anticipated primary outcome is a point estimate and confidence interval for the ICER, which will indicate the direction and magnitude of any cost-effectiveness difference between the intervention arms. A key theme to be explored is the trade-off between higher upfront costs and potential long-term health gains.", "conclusion": "The trial is designed to generate high-quality, policy-relevant evidence on the economic efficiency of different community health centre configurations.",