Enrollment estimates are rounded to the nearest 100. Figures may not sum due to rounding.

Enrollees are presumed to be unduplicated (each person is only counted once).

The enrollment estimates differ slightly from similar estimates posted by CMS because adjustments to the data have been made for several states where some individuals appeared to be categorized incorrectly. Our most common adjustment was to shift people age 65 and older to the aged category who were previously categorized as disabled, and our second most common adjustment was to shift individuals under age 65 out of the aged category and into the disabled category.

Some enrollees are only eligible for a limited set of benefits. A small fraction of elderly and disabled enrollees in every state qualify only for assistance with their Medicare premiums and coinsurance. In 2004, a few states also had waivers that allowed them to enroll relatively large numbers of people in Medicaid-funded programs for family planning-related services or prescription drug coverage.

The Urban Institute and Kaiser Commission on Medicaid and the Uninsured estimates based on data from Medicaid Statistical Information System (MSIS) reports from the Centers for Medicare and Medicaid Services (CMS), 2009.

Enrollees: Individuals who participate in Medicaid for any length of time during the federal fiscal year. They may not actually use any services during this period, but they are reported as enrolled in the program and are eligible to receive services in at least one month. Tables produced by CMS may use the term "eligibles" to describe these individuals.
Elderly: Includes all people age 65 and older.
Disabled: Includes younger persons (age 64 and under) who are reported as eligible due to a disability.
Adults: Generally people age 18 to 64
Children: Generally people age 17 and younger.
However, some people under age 18 may be classified as "adults" and some people age 18 and older may be classified as "children" depending on why they qualify for the program and each state''s practices.

Federal Fiscal Year: Unless otherwise noted, years proceeded by "FY" on statehealthfacts.org refer to the Federal Fiscal Year, which runs from October 1 through September 30. For example, FY 2009 refers to the period from October 1, 2008 through September 30, 2009.