The CMS BSA Outpatient Procedures PUF contains claims for a simple random sample of 5% of the 2010 beneficiary population. Out of approximately 2.5 million beneficiaries in the 5% sample, about 1.2 million had claims, resulting in a PUF of 33,600,194 procedures, after protecting the privacy of Medicare beneficiaries. It contains six analytic variables (in addition to a unique procedure key): Age, gender, ICD‐9 primary diagnosis code, HCPCS procedure code, count of the number of services, and Medicare payment for procedures. Some of these variables are aggregated or coarsened in order to protect individuals from identification while retaining the analytic value of the data.
A procedure is only included in the PUF if the combination of all six variables is shared by at least eleven beneficiaries in the population. Procedures cannot be linked by claim or beneficiary and cannot be linked to any external data source by means of the procedure ID. The procedure ID is a cryptographic key specific to this Outpatient Procedures PUF and not available elsewhere. The CMS 2010 BSA Outpatient Procedures PUF is sorted by this procedure ID to ensure that the relative positions of each procedure in the PUF and in the original source data are totally uncorrelated. BSA Outpatient Procedures PUF contains seven variables: A procedure count and six analytic variables, listed below.