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Health Insurance Coverage Measurement in the Annual Social and Economic Supplement to the Current Population Survey (CPS ASEC) and the American Community Survey (ACS)

Each fall, the U.S. Census Bureau releases two sources for health insurance statistics in the United States: The Annual Social and Economic Supplement to the Current Population Survey (CPS ASEC) and the American Community Survey (ACS).

Survey Background

The CPS ASEC has produced health insurance statistics every year since 1987, making it one of the most widely used sources of statistics on health insurance coverage in the United States. The survey provides information on health insurance status (insured or not insured) for the nation and by demographic groups. Detailed income data available from the CPS ASEC also make it possible to view changes in health insurance coverage in relation to changes in the overall economic well-being of the nation. In 2014, after more than a decade of research, the Census Bureau implemented redesigned health insurance questions to improve its measure of health insurance coverage for calendar year 2013 and beyond. In 2019, the Census Bureau introduced an updated processing system to take full advantage of this new content.

Starting in 2008, the Census Bureau also began asking about health insurance coverage using the ACS. Its large sample size makes it possible to obtain health insurance coverage estimates for subnational geographies, including states, counties, metro areas, congressional districts and cities. This level of geographical detail is not available from any other survey that collects data on health insurance coverage. The ACS can also provide historic comparisons back to 2008.

Differences Between the Two Surveys

The two surveys differ in the timing of data collection, the reference period, the time frame of the resulting health insurance coverage estimates, and, ultimately, in uses of the data.

In the CPS ASEC, which is conducted in February through April, respondents answer questions about whether they had health insurance coverage at any time in the previous calendar year. The survey, thus, measures if a person was insured on any day during the previous year. They are considered “uninsured” only if, for the entire year, they had no coverage under any type of health insurance.1

With the updated processing system in 2019, the CPS ASEC also includes a measure of coverage at the time of interview. For information about current health insurance coverage and how it differs from the primary measure of coverage in the CPS ASEC, see <https://www.census.gov/newsroom/blogs/research-matters/2019/09/current-coverage.html>.

In contrast, the ACS is a rolling sample of households collected continuously all year long. The survey asks if a person is currently covered by any of the listed types of health insurance. So, the ACS measures health insurance for the population based on whether people are insured at the point-in-time that they answered the survey during the year of collection.

There is also a variety of differences in the survey logistics. Census Bureau field representatives conduct the CPS ASEC by personal visit or telephone. For the ACS, although some respondents are visited by a field representative, many respondents reply via a paper form or reply via the Internet. Because of space limits within a paper survey, the ACS asks fewer and less detailed questions than the CPS ASEC. In addition, the ACS asks about the insurance coverage of each household member specifically, while the CPS ASEC asks if anyone in the household is covered, and, if so, who that is.

With these variations and others, the two surveys produce consistent, though slightly different statistics on health insurance coverage.

 1In both the CPS ASEC and ACS, respondents who are only covered by the Indian Health Service (IHS) are considered to be uninsured. IHS coverage is not considered to be comprehensive.


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