What are some limitations of each category of files?
RIFs: • Researchers must go through a rigorous process to obtain RIF data. See Requesting CMS RIF Data LDS: • Selected variables are encrypted, ranged or blanked: UPIN is encrypted, beneficiary age is ranged (by age groups), dates of service are by quarter and year, zip codes are blank (the lowest level of cross-sectional analysis is the county level for the SAFs and the state level for the MedPAR File). The LDS SAFs have a specific beneficiary key that allows the LDS SAFs to be linked; the LDS MedPAR file cannot be linked with any of the LDS SAFs. Non-identifiable Files: • No patient-or physician-specific data.
