Medicaid provides health insurance coverage to more people than any other single program in the United States, with coverage for low-income children, adults, seniors, and those with disabilities.1 As of March 2017, there were 74 million Medicaid and Children’s Health Insurance Program (CHIP) enrollees, of which nearly 36 million were enrolled in CHIP or were children enrolled in Medicaid, according to the Center for Medicaid and CHIP Services.2

For a more detailed breakdown of people covered by Medicaid and other means-tested health insurance programs (like CHIP and others, listed in more detail below), we turned to the American Community Survey (ACS).3

As shown in the table below, children and youth represent nearly half of all people covered by means-tested public health insurance in the United States. Adults ages 65 and older, many of whom are low-income and participate in Medicaid to supplement Medicare, represent nearly 11 percent. Disabled and institutionalized adults account for another 14 percent, and women who have given birth in the past year represent just under 2 percent. These vulnerable groups account for more than seven in 10 participants in means-tested health insurance programs. Of those remaining, 12 percent work full time or part time. In short, Medicaid and CHIP participants are among the most vulnerable members of the U.S. population.

Table: The Majority of Publicly Insured Individuals Are Children, Older Adults, or Disabled.

Category of Participant

Number in 2015

Percent

Cumulative Percent

Child/Youth (under age 19)

30,419,902

45.8

45.8

Ages 65 and Older

7,155,401

10.8

56.6

Disabled (ages 19-64)

8,781,327

13.2

69.8

Institutionalized (ages 19-64)

380,517

0.6

70.4

Recent Mother (ages 19 and older)

1,040,193

1.6

71.9

Working Full Time Year Round (ages 19-64)

4,678,142

7.0

79.0

Working Part Time or Part Year (ages 19-64)

3,319,811

5.0

84.0

Other

10,641,447

16.0

100.0

TOTAL Means-Tested Public Health Insurance

66,416,740

100.0


Table only available on Desktop

Notes: Categories are mutually exclusive. Full-time, year-round work includes those working 35 hours or more per week, 50 or more weeks per year. Part time includes those working at least 10 hours per week, at least 47 weeks per year, excluding full-time, year-round workers.

Source: Population Reference Bureau analysis of U.S. Census Bureau, American Community Survey, 2015.

Using the ACS to Study Medicaid Recipients

In 2008, the Census Bureau added a question to the ACS asking about respondents’ current health insurance coverage. Individuals can have more than one type of insurance, and the data are broadly sorted into either private health insurance or public coverage. Public health insurance can be further broken down into Medicare, means-tested programs, and Veterans Administration health care. Means-tested health care includes:

  • Medicaid or Medical Assistance: Coverage for those with low-income or a disability (can vary by name in different states).
  • Children’s Health Insurance Program (CHIP): State-run programs for low-income children whose parents do not qualify for Medicaid.
  • Other means-tested programs: For example, state-specific plans that cover low-income uninsured individuals, such as county indigent services.

In the ACS, Medicaid health insurance is grouped with CHIP and with (considerably less common) other means-tested health care. This grouping occurs, at least in part, because survey respondents may not know which type of public coverage they have. Individual states may refer to their Medicaid and CHIP programs by different names (for example, the Medicaid program in California is known as Medi-Cal, and the CHIP program is referred to as Healthy Families). Further complicating matters, states may use the same name for more than one type of health insurance (for example, California manages both Medicaid and CHIP health insurance under the umbrella name Medi-Cal).

Taking these considerations into account, we analyzed the characteristics of people with means-tested public health insurance coverage (Medicaid, CHIP, or other public insurance) using 2015 ACS data.

Conducting Research With Medicaid Data

Various data sources are available to analyze the Medicaid program. Administrative data provide point-in-time counts and allow users to analyze trends in enrollment and program spending across time, but are limited in their ability to describe the people participating in the program. These data are not always available for public use or produced in a timely manner, making it difficult for researchers or policymakers to understand the program’s current effectiveness.

Conversely, surveys (such as the ACS) provide social and demographic data such as age, sex, education, and race/ethnicity, which can help researchers and policymakers better understand Medicaid recipients. Another added benefit is the capability for deeper analysis by adding population data as denominators to calculate rates and percentages.

There are also limitations to using survey data as a source for Medicaid-related research. Survey data tend to underestimate participation in social programs.4 Historical data may not be available, and national surveys may not accurately measure participation in state-specific programs. Despite these limitations, we used data from the ACS for this analysis because it provides detailed demographic data and is a nationally representative sample of the population.

Other Sources of Data on Medicaid Enrollment

National Survey Data

Current Population Survey (CPS): Provides demographic detail but cannot provide estimates of state-level coverage.

National Health Interview Survey (NHIS): Estimates both coverage status and length of time with coverage at time of interview but states must be combined to produce reliable annual estimates.

Medical Expenditure Panel Survey (MEPS): Contains detailed information covering two full calendar years that can be broken down into census regions (Northeast, Midwest, South, West).

Survey of Income and Program Participation (SIPP): Includes health care coverage status as well as disability status but cannot provide annual estimates.

Aggregate-Level Administrative Data

Medicaid Budget and Expenditure System (MBES): Aggregate enrolled data available quarterly, can be linked to claims data but lacks demographic detail.

Centers for Medicare & Medicaid Services (CMS) Performance Metric Data: Updated monthly and includes details by state and program.

Individual-Level Administrative Data

Medicaid Statistical Information System (MSIS): While not publicly available, can link enrollment and spending but lacks demographic characteristics.

Additional Resources

Census Bureau, “Health Insurance” https://www.census.gov/topics/health/health-insurance/about/glossary.html

Moving Medicaid Data Forward, Forum: Medicaid Enrollment—Overview and Data Sources https://www.mathematica-mpr.com/events/moving-medicaid-forward-part-2

Medicaid Pocket Primer

http://www.kff.org/medicaid/fact-sheet/medicaid-pocket-primer/


References

1. Henry J. Kaiser Family Foundation, “Why Does the Medicaid Debate Matter? National Data and Voices of People With Medicaid Highlight Medicaid’s Role,” (June 19, 2017), accessed at www.kff.org/medicaid/fact-sheet/why-does-the-medicaid-debate-matter-national-data-and-voices-of-people-with-medicaid-highlight-medicaids-role/, on June 26, 2017.
2. Medicaid.gov, “April 2017 Medicaid and CHIP Enrollment Data Highlights,” accessed at www.medicaid.gov/medicaid/program-information/medicaid-and-chip-enrollment-data/report-highlights/index.html, on June 26, 2017. 
3. Means-tested health insurance programs are available to people on the basis of income, age, or other qualifying condition (such as disability).
4. Brett Fried, State health access Data Assistance Center, “Medicaid Undercount in the American Community Survey: Preliminary Results,” (August 7, 2013), accessed at www.shadac.org/sites/default/files/publications/ACS_Undercount_JSM2013_BFried.pdf, on June 26, 2017.