A Summary of the CPS Sample Expansion,
With Report and Data Release Plans: 2001 and 2002
February 22, 2001

The State Children's Health Insurance Program, established in 1997, allocates funds to states based on a formula that uses data from the Current Population Survey (CPS). Specifically, the formula uses state-level data from the March CPS Annual Demographic Supplement (ADS) on the number of uninsured children under 19 years of age in families below 200 percent of the poverty thresholds. To reduce sampling error (variance), the formula uses a 3-year moving average rather than a single-year estimate.

In 2001, the sample for the ADS was expanded primarily to improve state estimates of children's health insurance coverage. The three components of the sample expansion are:

• Asking the March ADS questions of one-quarter of the February and April CPS samples, that is, of the households not also included in the March sample;

• Interviewing selected sample households from the preceding November CPS sample during the February-April period using the March ADS; and

• Increasing the monthly CPS sample in states with high sampling errors for uninsured children.

The Census Bureau will release some reports and files from both the original and the expanded samples in 2001. Initially, the September 2001 reports on health insurance, income, and poverty will use only the original sample. Following these publications, the Census Bureau will evaluate the estimates from the expanded sample and produce a supplementary research report with data from the entire sample. If the data are of acceptable quality, the Census Bureau plans to use data from the expanded sample in all of its CPS-based reports in 2002.

Assuming no significant problems are found, the Census Bureau plans to release three data files corresponding to the publication of the 2001 and 2002 reports:

• The original 2001 sample file in September 2001;

• A 2001 research file that contains data about all households, including those from the expanded sample, in the winter of 2001-2002; and

• A 2002 complete sample file in the autumn of 2002.

Please direct comments or suggestions about the sample expansion to:

Thomas Moore III
Chief, Health Surveys and Supplements Branch
Demographic Surveys Methods Division, Room 3720-3
U.S. Census Bureau
Washington DC 20233-8700

or by e-mail to Thomas.Francis.Moore.III@census.gov.

Direct comments or suggestions about the derived estimates to:

Charles Nelson
Assistant Division Chief for Income, Poverty and Health Statistics
Housing and Household Economic Statistics Division, Room 1069-3
U.S. Census Bureau
Washington DC 20233-8500

or by e-mail to Charles.T.Nelson@census.gov.

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