A Methodological Evaluation of System Reliability in Ethiopian Community Health Centres: A Difference-in-Differences Model

"background": "Community health centres are critical nodes in primary healthcare systems, yet robust methodological frameworks for evaluating their operational reliability are underdeveloped. This creates a significant evidence gap for health systems planning and resource allocation. ", "purpose and objectives": "This case study aims to methodologically evaluate the reliability of service systems in a network of community health centres. Its primary objective is to demonstrate the application of a quasi-experimental difference-in-differences (DiD) model to isolate the effect of a systemic intervention on facility reliability. ", "methodology": "We employ a longitudinal DiD design, analysing panel data from intervention and matched control facilities. The core statistical model is Y{it = \0 + \1 + \2 + \ (\) +, where Yit is a composite reliability index. Inference is based on cluster-robust standard errors to account for facility-level correlation. ", "findings": "The DiD estimator (\) indicated a positive and statistically significant improvement in system reliability for intervention centres. The point estimate corresponded to a 17. 5 percentage point increase in the composite reliability index (95% CI: 9. 2, 25. 8) relative to control facilities, with the effect being robust to several sensitivity checks. ", "conclusion": "The applied DiD model provides a rigorous methodological framework for attributing changes in health system performance to specific interventions, moving beyond descriptive assessments. It demonstrates the value of quasi-experimental designs in operational health systems research. ", "recommendations": "Health systems researchers should adopt quasi-experimental designs like DiD for evaluating complex service delivery interventions. Policymakers should mandate the collection of longitudinal, facility-level data to enable such analyses for evidence-informed decision-making. ", "key words": "health systems research, difference-in-differences, quasi-experimental design,