Public health surveillance systems play a crucial role in monitoring disease trends and managing public health emergencies efficiently. A randomized field trial was conducted with 10 urban centers across Nigeria. Data collection included patient symptoms, diagnostic tests, and treatment protocols over a six-month period. Findings indicate that the variability of symptom reporting between healthcare providers varied by up to 25% in some centers, necessitating standardised training programmes for improved data accuracy. The results underscore the need for structured training and standardization in public health surveillance systems to enhance clinical outcomes. Implementing a comprehensive quality assurance programme is recommended to ensure consistent reporting of patient symptoms across all healthcare facilities. Public Health Surveillance, Clinical Outcomes, Randomized Field Trial, Nigeria Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.