Health insurance coverage

Broadly defined to include both public and private payers that cover medical expenditures incurred by a defined population in a variety of settings. Estimates of health insurance are available from several different government surveys. Because of differences in methodology, question wording, and recall period, estimates from different sources may vary and are not directly comparable. For more information, see: “Health Insurance Measurement and Estimates,” available from: https://www.census.gov/content/dam/Census/library/working-papers/2015/demo/2015-Vornovitsy-Day-01.pdf.

National Health Interview Survey (NHIS)

Data on health insurance coverage for 1984, 1989, and 1994–1996 presented in Health, United States were assessed using the health insurance supplement in NHIS. For point-in-time health insurance estimates, NHIS respondents are asked about their coverage at the time of interview. For 1993–1996, respondents were asked about their coverage in the previous month. Questions on health insurance coverage were expanded starting in 1993 compared with previous years.

In 1997, the entire questionnaire was redesigned, and data were collected using a computer-assisted personal interview. Data from 1997 through 2018 on health insurance coverage were assessed using the Family Core questionnaire of NHIS. In 2007, questions on health insurance coverage were expanded again to include three new questions on high-deductible health plans, health savings accounts, and flexible spending accounts.

NHIS was redesigned again in 2019. Starting in 2019, health insurance coverage is assessed as part of the annual core in the Sample Adult and Sample Child questionnaires. The flow and content of questions regarding health insurance coverage are similar to those in the 1997–2018 Family Core questionnaire.

Private health insurance

Respondents are considered to be covered by private health insurance if they indicate private health insurance or, before 1997, if they were covered by a single-service hospital plan. Private health insurance includes managed care such as health maintenance organizations.

Private insurance obtained through the workplace was defined as any private insurance that was originally obtained through a present or former employer or union or, starting in 1997, through the workplace, self-employment, or a professional association. Starting in 2011, respondents were also asked whether health insurance coverage was obtained through parents or another relative. Starting in 2014, an additional question on the Health Insurance Marketplace was added to the questionnaire for those respondents who did not indicate that their health plan was obtained through a present or former employer, union, self-employment, or professional association, to evaluate whether their plan was obtained through the Health Insurance Marketplace or a state-based exchange.

Medicaid or other public assistance coverage

Until 1996, people were defined as having Medicaid or other public assistance coverage if they indicated that they had either Medicaid or other public assistance, or if they reported receiving Aid to Families with Dependent Children (AFDC) or Supplemental Security Income (SSI). After welfare reform in late 1996, Medicaid was delinked from AFDC and SSI. Starting in 1997, people are considered to be covered by Medicaid if they report having Medicaid or a state-sponsored health program. Starting in 1999, data for people covered by the Children’s Health Insurance Program are presented along with data for those with Medicaid coverage, due to the similar populations covered and ascertainment issues. Medicare or military health care coverage is also determined in the interview, and starting in 1997, other government-sponsored program coverage is determined as well. In 2018, a new question about Veterans Affairs health care enrollment and usage by veterans was added, improving accuracy in determining military health care coverage.

Two questions were added to the health insurance section of NHIS beginning with the third quarter of 2004 (HICov-Table). One question is asked of people aged 65 and over who had not indicated that they had Medicare: “People covered by Medicare have a card which looks like this. [Are/Is] [person] covered by Medicare?” The other question is asked of people under age 65 who had not indicated any type of coverage: “There is a program called Medicaid that pays for health care for people in need. In this state it is also called [state name]. [Are/Is] [person] covered by Medicaid?” Respondents who originally classified themselves as uninsured, but whose classification was changed to Medicare or Medicaid based on a “yes” response to either question, subsequently receive appropriate follow-up questions concerning periods of noncoverage for insured respondents. Of the 892 people (unweighted) who were eligible to receive the Medicare probe question in the third and fourth quarters of 2004, 55% indicated that they were covered by Medicare. Of the 9,146 people (unweighted) who were eligible to receive the Medicaid probe question in the third and fourth quarters of 2004, 3% indicated that they were covered by Medicaid. From 2004 onward, estimates in Health, United States are calculated using the responses to the two additional probe questions. For a complete discussion of the effect of the addition of these two probe questions on insurance coverage estimates, see: Cohen RA, Martinez ME. Impact of Medicare and Medicaid probe questions on health insurance estimates from the National Health Interview Survey, 2004. NCHS Health E-Stats. 2005. Available from: https://www.cdc.gov/nchs/data/hestat/impact04/impact04.htm.

No health insurance

The remaining respondents who reported no coverage under any of the types of plans listed are considered uninsured. The uninsured are people who do not have coverage under private health insurance, Medicare, Medicaid, public assistance, a state-sponsored health plan, other government-sponsored programs, or a military health plan. People with only Indian Health Service (IHS) coverage are considered uninsured. Although NHIS respondents who report IHS coverage as their only source of coverage are currently recoded to being uninsured, IHS provides a comprehensive health service delivery system for about 2.2 million American Indian or Alaska Native people. For more information, see: https://www.ihs.gov/newsroom/factsheets/ihsprofile/ and https://www.ihs.gov/forpatients/. Estimates of the percentage of people who are uninsured based on NHIS may differ slightly from those based on other sources because of differences in survey questions, recall period, and other aspects of survey methodology.

Additional considerations

About 1% of NHIS respondents did not know or refused to provide information about their health insurance coverage. These respondents are considered to have unknown coverage and are excluded from the analyses. In Health, United States, the term “uninsured” refers only to the population under age 65.

For more information, see: Health insurance section (INS). In: 2019 National Health Interview Survey (NHIS) public use data release: Survey description. 2020. Available from: https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Dataset_Documentation/NHIS/2019/srvydesc-508.pdf. (Also see Sources and Definitions, Children’s Health Insurance Program; Fee-for-service health insurance; Health maintenance organization [HMO]; Managed care; Medicaid; Medicare; Uninsured.)

HICov. Percentage of people under age 65 with Medicaid or who are uninsured, by selected demographic characteristics, using Method 1 and Method 2 estimation procedures: United States, 2004

¹ Includes people who do not have private coverage but who have Medicaid or other state-sponsored health plans, including the Children’s Health Insurance Program (CHIP). See Sources and Definitions, Children’s Health Insurance Program.

² Includes people who have not indicated that they are covered at time of interview under private health insurance, Medicare, Medicaid, CHIP, a state-sponsored health plan, other government programs, or military health plan (including VA, TRICARE, and CHAMP–VA). This category includes people who are only covered by Indian Health Service (IHS) or only have a plan that pays for one type of service, such as accidents or dental care. See Sources and Definitions, Health insurance coverage.

³ Starting with the third quarter of 2004, two questions were added to the National Health Interview Survey (NHIS) insurance section to reduce potential errors in reporting of Medicare and Medicaid status. People aged 65 and over not reporting Medicare coverage were asked explicitly about Medicare coverage, and people under age 65 with no reported coverage were asked explicitly about Medicaid coverage. Estimates calculated without using the additional information from these questions are noted as Method 1. Estimates calculated using the additional information from these questions are noted as Method 2. See Sources and Definitions, Medicaid; Medicare.

⁴ Based on family income and family size and composition, using U.S. Census Bureau poverty thresholds. The percentage of respondents with unknown poverty level was 28.2% in 2004. See the NHIS survey description for 2004. Available from: https://www.cdc.gov/nchs/data/nhis/srvydesc.pdf.

⁵ People of Hispanic origin may be of any race or combination of races. Similarly, the category Not Hispanic or Latino refers to all people who are not of Hispanic or Latino origin, regardless of race.

SOURCE: National Center for Health Statistics, National Health Interview Survey, 2004, Family Core Component. Data are based on household interviews of a sample of the U.S. civilian noninstitutionalized population. For more information, see: Cohen RA, Martinez ME. Impact of Medicare and Medicaid probe questions on health insurance estimates from the National Health Interview Survey, 2004. National Center for Health Statistics. NCHS Health E-Stats. 2005. Available from: https://www.cdc.gov/nchs/data/hestat/impact04/impact04.htm. See Sources and Definitions, National Health Interview Survey (NHIS).