The central role of the propensity score analysis (PSA) in observational studies is for causal inference; as such, PSA is often used for making causal claims in research articles. However, there are still some issues for researchers to consider when making claims of causality using PSA results. This summary first briefly reviews PSA, followed by discussions of its effectiveness and limitations. Finally, a guideline of how to address these concerns is also provided for researchers to make appropriate causal claims using PSA results in their research articles.