"background": "Public health surveillance systems are critical for disease control and health policy. In South Africa, evaluating the performance and yield of these systems is essential for resource allocation and improving public health outcomes, yet a comprehensive methodological synthesis is lacking. ", "purpose and objectives": "This meta-analysis aims to methodologically evaluate studies on public health surveillance systems in South Africa and to employ panel-data estimation techniques for quantifying yield improvement over time. ", "methodology": "A systematic search identified relevant studies. Methodological quality was assessed using a modified Newcastle-Ottawa Scale. Quantitative synthesis employed a random-effects meta-analysis of standardised yield measures. The core panel estimation model was Y{it = \0 + \1 Tit + \2 Xit + \ +, where Yit is the yield outcome for system i at time t, T is a time trend, X is a vector of covariates, \ denotes system-specific effects, and \₈ₓ is the error term. Inference was based on cluster-robust standard errors. ", "findings": "The methodological review revealed significant heterogeneity in evaluation frameworks, with 65% of studies lacking a formal cost-effectiveness component. The panel-data estimation showed a positive but statistically non-significant annual trend in surveillance yield (β = 0. 03, 95% CI: -0. 01, 0. 07), indicating that systemic improvements have been marginal without targeted intervention. ", "conclusion": "While surveillance infrastructure has expanded, methodological rigour in evaluation remains inconsistent, and yield gains have been modest. The application of panel-data methods provides a robust framework for longitudinal performance assessment. ", "recommendations": "Future evaluations should adopt standardised metrics incorporating cost and outcome data. Investment should focus on integrating data systems and building analytical capacity to translate surveillance data into actionable public health gains. ", "key words": "public health surveillance,
Nkosi et al. (Mon,) studied this question.