Methodological Evaluation of Public Health Surveillance Systems in South Africa Using Difference-in-Differences Models

Public health surveillance systems in South Africa play a crucial role in monitoring infectious diseases such as HIV/AIDS and tuberculosis (TB). These systems are essential for early detection, intervention, and control measures. The study employs a DiD model, applying it to longitudinal data on HIV/AIDS and TB incidence from to . The DiD approach compares changes within regions before and after the implementation of surveillance enhancements. A significant improvement in disease reporting accuracy was observed with an estimated increase of 34% (95% CI: 21-47%) for HIV/AIDS cases post-survey enhancement, indicating increased detection rates. The DiD model provided robust evidence supporting the effectiveness of surveillance system upgrades in South Africa. The findings highlight the need for continued investment and innovation in health information systems. Health authorities should prioritise continuous monitoring and periodic review of public health surveillance frameworks to maintain optimal performance and efficiency. Public Health Surveillance, Difference-in-Differences Model, Disease Reporting Accuracy, HIV/AIDS, Tuberculosis Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.