Monthly values for the first of up to 16 managed care plan type codes: A model of health care delivery organized to provide a defined set of services in the month. There are separate variables for each of the 12 months during the year. The last two digits of this variable indicate the month.
For each month, there are up to 16 managed care plan type codes; the sequence (1st16th plan type codes) is indicated by the 3rd and 4th digits from the right (e.g., MC_PLAN_TYPE_CD_05_MM) is the monthly variable string for the 5th MC plan type.
The monthly MC_PLAN_ID_01_MM corresponds to the managed care plan type code (MC_PLAN_TYPE_CD_01_MM) for the same month.
SOURCE: T-MSIS Annual Demographic and Eligibility TAF