Monthly Medicare-Medicaid dual eligibility code - October

SAS Name

This variable indicates whether the beneficiary was eligible for both Medicare and Medicaid in a given month (October).


The original source for this variable is the State Medicare Modernization Act (MMA) files that states submit to CMS. Those files are considered the “gold standard” for identifying dual eligibles because the information in them is used to determine the level of Medicare Part D low-income subsidies. Unlike most states, Puerto Rico and the Virgin Islands do not submit dual eligibility data to CMS through the MMA files. Consequently, the Master Beneficiary Summary File significantly undercounts dual-eligibles from these territories currently. Users should consider this variable to be incomplete when constructing an analysis population that includes dual-eligibles from these two territories. Dual eligibles are often divided into “full duals” and “partial duals” based on the level of Medicaid benefits they receive. CMS generally considers beneficiaries to be full duals if they have values of 02, 04, or 08, and to be partial duals if they have values of 01, 03, 05, or 06. Partial duals sometimes divided into the QMB-only population (01) and all other partial duals (03, 05, or 06). There are different ways to classify dually eligible beneficiaries. Additional information regarding various ways to identify dually enrolled populations, refer to a CCW Technical Guidance document entitled: "Options in Determining Dual Eligibles." There are 12 monthly variables — where the 01 through 12 at the end of the variable name correspond with the month (e.g., 01 is January and 12 is December).

Source: CMS Common Medicare Environment (CME)


Code Code value
NA Non-Medicaid
00 Not enrolled in Medicare for the month
01 Qualified Medicare Beneficiary (QMB)-only
02 QMB and full Medicaid coverage, including prescription drugs
03 Specified Low-Income Medicare Beneficiary (SLMB)-only
04 SLMB and full Medicaid coverage, including prescription drugs
05 Qualified Disabled Working Individual (QDWI)
06 Qualifying individuals (QI)
08 Other dual eligible (not QMB, SLMB, QWDI, or QI) with full Medicaid coverage,
including prescription Drugs
09 Other dual eligible, but without Medicaid coverage
99 Unknown