Health Insurance

Skip top of page navigation
Census.govPopulation Health Insurance Main About Health Insurance

About Health Insurance

The Census Bureau produces health insurance data from three surveys and one model-based program. Depending on your needs, one data source may be more suitable than another data source. The following is a list of programs from the Census Bureau:

  1. CPS ASEC: The Annual Social and Economic Supplement to the Current Population Survey
  2. ACS: The American Community Survey
  3. SAHIE: The Small Area Health Insurance Estimates Program
  4. SIPP: The Survey of Income and Program Participation

The programs differ in length and detail of the survey questionnaire, the number of households interviewed, the methodology used to collect and process the data, and consequently, in the health insurance estimates produced. As a result, it is important to understand how different surveys and methods produce different results, and when it is appropriate to use each survey or method. More information on each data source is available in the U.S. Census Bureau Health Insurance Data Source Comparison table. [XLS - 49k].

The chart below summarizes the recommendations at various geographic levels:

Figure 1. U.S. Census Bureau Health Insurance Data Source Recommendations

Geographic Level

Cross-Sectional Estimates

Longitudinal Estimates

United States

CPS ASEC for income
ACS for detailed race groups



ACS/CPS ASEC 2-year averages 1

SIPP (selected states)

Substate (areas with populations of 65,000 or more)

SAHIE for counties, else 
ACS 1-year period estimates


Substate (areas with populations of 20,000 to 65,000)

SAHIE for counties, else
ACS  3-year period estimates2


Substate (areas with populations less than 20,000)

SAHIE for counties, else
ACS  5-year period estimates 3


1 Use CPS ASEC non-overlapping 2-year averages when examining state trends that include years prior to 2008.
2 ACS recommends using non-overlapping periods for trend analysis with multiyear estimates. For example, comparing 2005-2007 ACS 3-Year estimates with 2008-2010 ACS 3-Year estimates is preferred for identifying change.
3 ACS recommends using non-overlapping periods for trend analysis with multiyear estimates. For example, comparing 2006-2010 ACS 5-Year estimates with 2011-2015 ACS 5-Year estimates is preferred for identifying change.

The Annual Social and Economic Supplement (ASEC) to the Current Population Survey (CPS)

The CPS is a monthly survey conducted by the Census Bureau for the Bureau of Labor Statistics mainly to estimate the unemployment rate. The Annual Social and Economic Supplement (ASEC) to the CPS is a survey of about 100,000 addresses (which amounts to about 78,000 households) and includes detailed health insurance questions. The household respondent is asked if anyone in the household had specific types of health coverage during the previous calendar year, and if so, who. Interviews are conducted from February through April, and ask about the prior calendar year.


  • is mainly useful for examining timely estimates of the insured and uninsured population at the national level.
  • can be used for state-level estimates, trends, and differences (through multi-year averages), although the large sampling errors of state-level data limit its usefulness.
  • is the most widely used source of data on health insurance coverage in the United States, with a consistent time series of estimates from 1999 to 2012 (i.e. 2000 CPS ASEC to the 2013 CPS ASEC) and another time series that begins with 2013 (i.e. 2014 CPS ASEC).


The American Community Survey

The ACS is an ongoing nationwide survey that is conducted throughout the year. In the United States and Puerto Rico, about 250,000 addresses per month receive the ACS. Respondents are asked whether each household member is currently covered (by specific types of health coverage) at the time of interview.

The ACS:

  • is recommended for examining subnational data.
  • can be used to examine local-area estimates including counties, places, metropolitan areas, congressional districts, and other geographies.
    • The one-year ACS data is capable of generating estimates for geographies with populations of 65,000 or more.
    • The three-year ACS data is capable of generating estimates for those with 20,000 or more.
    • The five-year ACS data can be used for estimates at the sub-county level including census tracts and block groups in addition to all counties, places and other geographies.
  • began capturing health insurance data in 2008.


The Small Area Health Insurance Estimates Program

Small Area Health Insurance Estimates (SAHIE) is an ACS-enhanced product; model-based estimates of health insurance coverage for counties and states. The SAHIE program models health insurance coverage by combining survey data with population estimates and administrative records. SAHIE releases estimates of health insurance coverage by age, sex, race, Hispanic origin, and income categories at the state-level and by age, sex, and income categories at the county-level.


  • is recommended for examining single-year recent estimates for all US counties.
  • provides estimates that are more current than the ACS five-year estimates.
  • increases the precision of state- and county-level coverage for detailed demographic groups, and adds additional income categories of relevance to changes in healthcare laws.
  • has an interactive data, mapping, and trending tool that allows data users to customize and export tables, maps, and charts.
  • provides estimates beginning in the year 2000.


The Survey of Income and Program Participation

The SIPP is a longitudinal survey that interviews the same respondents, three times a year, for up to four years. Sample sizes range from approximately 14,000 to 36,700 interviewed households. Each household member (over age 15) is asked whether or not they were covered in each of the prior 4 months by Medicare, Medical Assistance, and other forms of health insurance. Household members under age 15 are asked indirectly through an adult.


  • is useful for examining monthly dynamics across time at the national level (such as how long a person remains uninsured, how many people obtain coverage, and any changes in a person’s coverage within a given year).
  • can be used to examine a limited number of sub-national geographies, including region and certain states.
  • provides rich detail on health insurance and many other topics extending back to 1984.



The CPS ASEC provides the most timely and accurate national data on health insurance with income detail. Hence, it is the preferred source for national analysis. The ACS is preferred for subnational data on health insurance by detailed demographic characteristics, due to its large sample size. The Census Bureau recommends using the ACS for single-year estimates of health insurance at the state level. Users looking for consistent, state-level trends before 2008 should use the CPS ASEC.

For sub-state areas such as counties, users should consider their specific needs when picking the appropriate data source. The SAHIE program produces single-year estimates of number and percent insured/uninsured by some demographic and income groups. SAHIE has standard errors mostly smaller than direct survey estimates. Therefore, SAHIE is the preferred source if it produces estimates for all of your characteristics of interest. Users who need estimates of health insurance coverage by other characteristics such as occupation should use the ACS, where and when available.

The SIPP is the only Census-provided source of longitudinal health insurance coverage estimates. It provides national estimates, as well as estimates for some larger states. As SIPP collects monthly data over 2 ½ to 4 year panels, it is also a source of health insurance coverage estimates for a time period of more or less than one year.

Note that Figure 1 is a summary of general recommendations. There are a number of considerations users should take into account when selecting a data source. For example, it is generally advisable to use the same data source for a particular purpose across all levels of geography.

The National Health Interview Survey (NHIS) is collected by the Census Bureau and released by the National Center for Health Statistics (NCHS). The Census Bureau recommends the NHIS when examining health outcomes. Links to the NHIS and other surveys that currently collect or have collected health insurance data can be found at Related Sites. Please note the list of external surveys is not exhaustive.

[Excel] or the letters [xls] indicate a document is in the Microsoft® Excel® Spreadsheet Format (XLS). To view the file, you will need the Microsoft® Excel® Viewer Off Site available for free from Microsoft®. This symbol Off Site indicates a link to a non-government web site. Our linking to these sites does not constitute an endorsement of any products, services or the information found on them. Once you link to another site you are subject to the policies of the new site.
Source: U.S. Census Bureau | Health Insurance |  Last Revised: June 25, 2015