Abstract
{ "background": "Public health surveillance systems are critical for disease control and resource allocation. In Ethiopia, evaluating the yield improvement of these systems requires robust methodological approaches, particularly those utilising longitudinal data to account for temporal and spatial heterogeneity.", "purpose and objectives": "This systematic review aims to critically evaluate the methodological approaches used in the literature to assess yield improvement in Ethiopia's public health surveillance systems, with a specific focus on the application and rigour of panel-data estimation techniques.", "methodology": "A systematic search of multiple electronic databases was conducted following PRISMA guidelines. Studies were screened against pre-defined inclusion criteria focusing on methodological design. Data were extracted on study characteristics, statistical models, estimation techniques, and reported measures of uncertainty. The quality of methodological application was appraised using a custom tool.", "findings": "Of the 27 included studies, a predominant theme was the use of two-way fixed effects models, specified as $Y{it} = \\beta X{it} + \\alphai + \\lambdat + \\epsilon_{it}$, where $i$ and $t$ index districts and years, respectively. However, only 33% reported robust standard errors or conducted sensitivity analyses for key model assumptions. The direction of association between integrated surveillance interventions and yield was consistently positive, though the magnitude of reported effects varied considerably.", "conclusion": "The application of panel-data methods for evaluating surveillance yield in Ethiopia is increasing but remains methodologically inconsistent. A lack of reporting on inference robustness and diagnostic testing limits the reliability of many published estimates.", "recommendations": "Future research should prioritise the use of more flexible panel-data estimators, rigorously report diagnostic tests for model assumptions, and explicitly quantify uncertainty using confidence intervals. Capacity building in advanced econometric techniques for public health researchers is urgently needed.", "key words": "surveillance systems, yield, panel data, fixed effects, econometric evaluation, methodology, health systems", "contribution statement": "This review provides the first formal methodological critique of panel-data