CMS’ longstanding standard policy has been to recommend a 15 percent oversampling for RMTS to ensure a valid response rate of at least 85 percent or include all nonresponses as non-Medicaid and unallowable.
In general, all completed responses should be used in an RMTS. However, CMS allows for the use of an alternate methodology in cases where the TSIP specifies an oversample to ensure an adequate number of valid responses for the treatment of time study nonresponses are achieved. The alternate methodology CMS historically has approved uses an 85 percent valid response rate. CMS recommends an oversample of 15 percent to ensure an adequate number of valid responses are received and to meet the required precision level. Per page 113 of the 2023 Comprehensive Guide to Medicaid Services and Administrative Claiming, an oversample may be used only to compensate, not substitute, for the potential number of nonresponses.