... allowing for a one monthbreak in Medicare A or B coverage (or allowing one monthof managed care coverage), rather than requiring fullMedicare coverage for a 12 month surveillance period,allows for ... enrollment/eli-gibility information from January 1, 2000 forward. A ran-dom 5% sample of Medicare beneficiaries is the standarddata file available to researchers, although the databasecontains information for 100% ... of death (i.e., covered for every alive and eligiblemonth, or covered for all except one of the alive and eligi-ble months), and who had one month or less of managedcare coverage, were considered...