Obtaining a Medically Underserved Area (MUA) designation involves application of the Index of Medical Underservice (IMU) to data on a service area to obtain a score for the area. The IMU scale ranges from zero to 100, with zero representing a completely underserved area and 100 representing a completely served area. Under the established criteria, each service area found to have an IMU of 62.0 or less qualifies for designation as a MUA.

The IMU involves four variables:

1. Ratio of primary medical physicians per 1,000 population
2. Infant mortality rate
3. Percentage of the population with incomes below the federal poverty
    level
4. Percentage of the population age 65 or over

The value of each of these variables for the service area is weighted according to established criteria. The four values are summed to obtain the area's IMU score.

• Whole county (in non-metropolitan areas)
• Non-metropolitan areas with population centers within 30 minutes travel time of each other, groups  of contiguous counties (minor civil divisions [MCDs] or census county divisions [CCDs])
• Metropolitan areas, a group of census tracts (CTs) that represent a neighborhood due to homogeneous socioeconomic and demographic characteristics
• Non-single-county service areas, the rationale for the selection of a particular service area in terms of market patterns or composition of population should be presented (designation requests should also include a map showing the boundaries of the service area involved and the location of resources within this area)

B. The latest available data on:

Resident civilian, non-institutional population of the service area (aggregated from individual county, MCD/CCD or CT population data)

• Percentage of the service area's population with incomes below the federal poverty level
• Percentage of the service area's population age 65 and over
• Infant mortality rate (IMR) for the service area, county or sub-county area (the latest five-year average should be used to assure statistical significance; sub-county IMRs should be used only if they involve at least 4,000 births over a five-year period)
• Current number of full-time equivalent (FTE) primary care physicians providing patient care in the service area and their locations of practice (patient care includes seeing patients in the office, on hospital rounds and in area; an applicant should check state and local physician licensure lists, state and local medical society directories, local hospital admitting physician listings, Medicaid and Medicare provider lists, and the local phone book)
• Computed ratio of FTE primary care physicians per one thousand population for the service area. The IMU for the service area is then computed from the above data using the conversion Tables VI-V4 detailed in the criteria, which translate the values of each of the four indicators into a score; the IMU is the sum of the four scores)