{ "background": "Community health centres are a cornerstone of primary care delivery in many low-resource settings, yet rigorous quantitative evaluations of their systemic efficiency gains are limited. Existing assessments often lack robust counterfactuals, making causal attribution challenging.", "purpose and objectives": "This case study aimed to develop and apply a quasi-experimental methodology to isolate and quantify the causal effect of a national community health centre strengthening programme on health system efficiency in Uganda.", "methodology": "We employed a difference-in-differences model, comparing changes in key efficiency indicators (e.g., outpatient cost per visit) between treatment facilities (n=127) and matched control facilities (n=127) before and after programme implementation. The core model is specified as: $Y{it} = \\beta0 + \\beta1 \\text{Treat}i + \\beta2 \\text{Post}t + \\delta (\\text{Treat}i \\times \\text{Post}t) + \\epsilon_{it}$, where $\\delta$ is the causal parameter of interest. Inference is based on cluster-robust standard errors at the facility level.", "findings": "The intervention led to a statistically significant reduction in the average outpatient cost per visit of 18.2% (95% CI: -22.1% to -14.3%, p<0.01) in treatment centres relative to controls. This efficiency gain was primarily driven by improved supply chain management and task-shifting, as identified in supplementary qualitative fieldwork.", "conclusion": "The community health centre model, when supported by a targeted strengthening programme, can produce substantial and measurable efficiency improvements within a constrained health budget.", "recommendations": "Policy makers should integrate quasi-experimental evaluation designs, particularly difference-in-differences, into the rollout of health system interventions to rigorously monitor efficiency. Investment should prioritise integrated supply chain systems and supportive supervision for frontline health workers.", "key words": "health systems, efficiency, difference-in-differences