{ "background": "District hospitals are critical nodes in Nigeria's healthcare system, yet their operational efficiency remains a persistent challenge. Systematic evaluations of the methodologies used to analyse these systems are lacking, particularly concerning advanced statistical approaches that account for hierarchical data structures.", "purpose and objectives": "This systematic review aims to critically appraise the application of multilevel regression models in studies evaluating the efficiency of district hospital systems, assessing methodological rigour, model specification, and the inferential value of findings for health systems policy.", "methodology": "A systematic search of multiple electronic databases was conducted following PRISMA guidelines. Peer-reviewed studies employing multilevel modelling to analyse hospital efficiency data were included. Data were extracted on model specifications, variables, and statistical reporting. Quality assessment used a bespoke tool for quantitative health systems research.", "findings": "Of the 27 included studies, a dominant theme was the poor reporting of model diagnostics and uncertainty measures; only 33% reported robust standard errors or confidence intervals for key coefficients. The typical model structure was a two-level random intercept model, $y{ij} = \\beta{0} + \\beta X{ij} + u{j} + e{ij}$, where $uj$ represents hospital-level random effects. Findings on efficiency drivers were inconsistent, partly due to heterogeneous variable selection.", "conclusion": "While multilevel regression is a theoretically appropriate tool for analysing hospital efficiency, its application in this context is often methodologically flawed, limiting the reliability and comparability of results for informing resource allocation.", "recommendations": "Future research must adhere to stricter reporting standards for multilevel models, including variance partition coefficients and diagnostics for random effects. Policymakers should require such methodological transparency when commissioning efficiency studies to ensure robust evidence.", "key words": "health systems research, multilevel modelling, hospital efficiency, methodological review, Nigeria", "contribution statement": "This review provides the first methodological synthesis of multilevel regression applications in Nigerian hospital efficiency research, establishing a novel checklist for critical