By Brett O’Hara
Next week, the U.S. Census Bureau is releasing two sources for health insurance statistics in the United States: the Annual Social and Economic Supplement to the Current Population Survey and the American Community Survey. While both surveys have questions that attempt to measure the same phenomena, they go about it in different ways.
Since 1987, the Current Population Survey has produced health insurance statistics every year, making it one of the most widely used sources of statistics on health insurance coverage in the United States. It provides statistics on health insurance status (insured or not insured), as well as the type of coverage, for the nation and by demographic groups, and shows us trends over the last couple of decades (See blog on recent changes to the Current Population Survey)
Starting in 2008, the Census Bureau also began asking about health insurance coverage using the American Community Survey. With its much larger sample size, we can see health insurance statistics for a broader range of geographic levels, including all 50 states, all counties and metro areas, and many other small geographic areas.
Many people ask us which estimate to use for a particular purpose. Our answer differs this year as we introduced a new set of health insurance coverage questions in the Current Population Survey Annual Social and Economic Supplement.
Both surveys obtain a person’s health insurance status by asking if they have insurance through a number of different sources, such as an employer, directly through an insurance company, Medicare, Medicaid, Veterans Administration and other public sector insurance, and the military. However, the surveys differ in both their times of collection and reference periods.
Like the other topics in the Current Population Survey’s Annual and Social and Economic Supplement, which is conducted in February, March and April, respondents answer questions about the previous calendar year. Specifically, we ask if 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.
In contrast, the American Community Survey is a rolling sample of households collected continuously all year long. We ask if a person is currently covered by any of the listed types of health insurance. So, the American Community Survey measures health insurance of 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 Current Population Survey by personal visit or telephone. For the American Community Survey, many respondents receive a paper form to complete and return in the mail. Because of space limits within a paper survey, the American Community Survey asks fewer and less detailed questions than the Current Population Survey. In addition, the American Community Survey asks about the insurance coverage of each household member specifically, while the Current Population Survey 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. Estimates from these two surveys rose and fell in parallel between 2009 through 2012. This degree of consistency between the two surveys collected under such different conditions gives us confidence that these statistics are useful for those who need to understand the state of health insurance coverage in America.
For this year, as always, the benefit of the Current Population Survey is the combination of detailed employment and detailed income data, along with the health insurance data, which provides an excellent overall picture of the well-being of our nation. However, to compare the 2013 estimates and previous years, there are other sources of health insurance coverage statistics, such as those from the American Community Survey and National Health Interview Survey. Also, because of the larger sample size and smaller sampling errors, we recommend using the American Community Survey for subnational geographies.