Abstract
{ "background": "Community health centres in Nigeria are critical for primary care delivery, yet their operational reliability is often compromised. Assessing the impact of interventions to improve system reliability requires robust methodological approaches. Quasi-experimental designs are frequently employed in this context, but their methodological rigour and appropriateness have not been systematically evaluated.", "purpose and objectives": "This systematic review aims to critically appraise the application of quasi-experimental designs in studies evaluating the reliability of community health centre systems in Nigeria, focusing on their methodological strengths, limitations, and analytical rigour.", "methodology": "A systematic search of multiple electronic databases was conducted following a pre-registered protocol. Eligible studies employed quasi-experimental designs to assess reliability outcomes in Nigerian community health centres. Study quality was assessed using a modified version of the ROBINS-I tool. Data were extracted on design characteristics, analytical methods, and key findings. A meta-analysis was not feasible due to heterogeneity; a narrative synthesis was performed.", "findings": "Of the 27 included studies, interrupted time series was the most common design (\(n=15)\). A key methodological weakness was the inadequate handling of confounding; only six studies used difference-in-differences models with propensity score matching. The primary analytical model was specified as $Y{it} = \\beta0 + \\beta1Tt + \\beta2Di + \\beta3(Tt \\times Di) + \\epsilon{it}$, where $Y_{it}$ is the reliability metric. Estimates from studies employing robust standard errors showed that intervention effects on drug availability were often non-significant (95% CI: -0.12 to 0.08).", "conclusion": "The application of quasi-experimental designs in this field is widespread but methodologically inconsistent. Many studies lack the analytical sophistication required to support strong causal inferences regarding interventions aimed at improving system reliability.", "recommendations": "Future research should prioritise more rigorous quasi-experimental designs, such as difference-in-differences with matching,