Community health centres in Kenya face challenges in delivering effective healthcare services. A systematic review was conducted, focusing on studies that utilised difference-in-differences (DiD) models to measure yield improvements. The search included databases like PubMed and Cochrane Library, with a focus on articles published between and in English. The analysis highlighted the use of DiD models for estimating yield improvement, particularly in improving healthcare service delivery efficiency. DiD models provided robust evidence for yield improvements in community health centres but varied results across different contexts necessitating further investigation. Further research should explore model applicability and effectiveness across diverse settings to ensure consistent yield improvements. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.