Detecting Potential Overbilling in Medicare Reimbursement via Hours Worked: Reply

Matsumoto (2020) pointed out data and coding errors in Fang and Gong (2017). We show that these errors have limited impacts: all qualitative findings remain after correcting them. Matsumoto also discussed potential service overcounting in the aggregated utilization data we used to illustrate our method, and then quantified the extent of overcounting with a sample of Medicare claims. We acknowledge the issue but discuss the noise and the bias in his quantification. Overall, our proposed method remains useful, as regulators who are interested in applying the method are unlikely to be subject to the data limitations.