This variable is the stand alone prescription drug plan (PDP) or Medicare Advantage Prescription Drug Plan (MA-PD) region code in which the plan benefit package provides coverage. Applies only to stand-alone PDPs and regional Medicare Advantage Prescription Drug plans.
The name associated with this region code can be found in the variable called (REGION_NAME).
The CCW constructs the Plan Characteristics File from information submitted by plan sponsors to CMS’s Health Plan Management System (HPMS).
Source: CMS (HPMS Files)