Propensity score matching is a method used to figure out if a treatment causes a certain outcome. Researchers choose factors that might affect the results, calculate a score, and match treated and untreated groups. It's important to check the assumptions made during this process, even though they can't be tested with the data available. By using what we know about the subject, we can reduce the chances of making mistakes. The purpose of the study guides which matching method to use and what to do after matching. Sensitivity analysis helps to see how reliable the results are. The researchers used real data to show these points in action.