District hospitals in Nigeria face challenges related to resource allocation and operational efficiency. A systematic review of literature was conducted using PRISMA guidelines. Studies were included if they utilised methods for assessing yield improvements in district hospitals within Nigeria. The analysis revealed that the most common methodological approach used in evaluating hospital systems involved regression models (e.g., $Y = a + bX + e$), with an average coefficient of determination ($R^2$) ranging from 0.4 to 0.6, indicating moderate explanatory power. The review highlighted the variability in methodological approaches and effectiveness across different studies, suggesting opportunities for standardization and improvement. Standardised yield assessment protocols should be developed and implemented to enhance operational efficiency in district hospitals. district hospitals, Nigeria, yield improvement, randomized field trial, regression models