The CMS 2008 BSA PDE PUF originates from a 5% simple random sample of beneficiaries drawn (without replacement) from the 100% Beneficiary Summary File for reference year 2008. The CMS 2008 PDE PUF contains thirteen variables. One of the analytic variables, strength of the drug, is provided in two pieces, (a) a numeric variable and (b) a text variable indicating the units. As they can be treated as one variable, there are eleven (11) rather than twelve (12) analytic variables, in addition to the claim ID.
The 100% Beneficiary Summary File is created annually and contains demographic, entitlement and enrolment data for beneficiaries:
– Who were documented as being alive for some part of the reference year of the Beneficiary Summary File, and
– Who were entitled to Medicare benefits during the reference year, and
– Who were enrolled in the Medicare Part A and/or Part B for at least one month in the reference year
The 5% sample of prescription drug events is created by collecting the prescription drug events for the beneficiaries in the 5% random sample of beneficiaries. The 5% random sample contains approximately 2.4 million beneficiaries. To create the CMS 2008 BSA PDE PUF, all claims that belong to those 2.4 million beneficiaries are collected. As part of the PUF preparation steps, some claims are excluded/suppressed from the CMS 2008 BSA PDE PUF.
The initial 5% sample of beneficiaries contains 2,392,893 beneficiaries. Out of the 2,392,893 beneficiaries, there are 1,265,691 beneficiaries with at least one prescription drug event, and the remaining 1,127,202 beneficiaries do not have any prescription drug events in 2008. To protect the privacy of Medicare beneficiaries, a total of 1,575,000 events incurred by 388,734 beneficiaries are suppressed from the PUF, leaving 50,325,988 events incurred by 1,264,083 beneficiaries in the CMS 2008 BSA PDE PUF. Suppressing an event may or may not exclude a beneficiary from the PUF. The exclusion of a beneficiary depends on whether or not the beneficiary has one or more additional events remaining in the PUF. Consequently, not all 388,734 beneficiaries are excluded.