Enhanced Medicare 5% Sample Indicator

SAS Name

This variable indicates whether the beneficiary was ever included in the CCW 5% sample for any year (1999+).


This enhanced 5% sample is broader than the annual 5% sample (variable that was previously called FIVE_PERCENT_FLAG; currently called SAMPLE_GROUP - when value ='01' or '04') because it includes all beneficiaries who were ever part of the 5% sample but had a HIC change that was not part of the sample. The "enhanced" indicator variable allows for longitudinal study of the 5% sample (i.e., once in, always in).

CCW creates the 5% sample using standard CMS processes. The 5% random sample consists of people who had a Medicare beneficiary Health Insurance Claim number (HIC) equal to the Claim Account Number (CAN) plus Beneficiary Identity Code (BIC) (HIC=CAN+BIC) where the last two digits of the CAN are in the set {05, 20, 45, 70, 95}.

Source: CCW (derived)


Code Code value
Y Yes, included in enhanced 5% sample
NULL Not included in enhanced 5% sample