Children's Health Insurance Patterns: A Review of the Literature. B. CPS ESTIMATES OF THE UNINSURED


The most commonly cited estimates of the number of uninsured children -- those produced by the Census Bureau, the Congressional Budget Office (CBO), the U.S. General Accounting Office (GAO), the Employee Benefit Research Institute (EBRI), and The Urban Institute -- use the March CPS as their source. The CPS, which is the source of the official Government statistics on employment and unemployment, is a nationally representative monthly survey of approximately 57,000 households in the United States. The sample is based on the civilian noninstitutionalized population of the United States, which includes persons living in households and group quarters (for example, college dormitories and rooming houses), but does not include residents of institutions (for example, homes for the aged) and persons living abroad. As well as being nationally representative, the sample is also representative of each of the 50 states and the District of Columbia, although for most states the samples are too small for precise state-level estimates.

The main purpose of the survey is to collect, by means of personal interviews, information on the employment status of the population during the survey month. In addition, supplemental questions are regularly added to the core questionnaire on topics such as health, education, income, and previous work experience. The March CPS contains supplemental questions on the health insurance status of each person in the household in the prior calendar year. Specifically, respondents are asked whether they had any of various types of private or public health insurance in the previous year. Respondents are permitted to report more than one type of health insurance coverage, although it is impossible to tell from the data whether persons with multiple types of coverage had the coverage concurrently or at different times during the previous year. The health insurance portion of the March 1995 CPS questionnaire is presented in Appendix A.

Respondents are never asked directly whether they were uninsured in the previous year. Instead, estimates of the uninsured are calculated as a residual -- that is, the uninsured are all those who do not report having some type of coverage in the previous year. As a result, the uninsured are those without any coverage throughout the previous year. However, some researchers believe that the CPS estimates of the uninsured are too high and, thus, that respondents may be reporting their health insurance status as of the interview date. This and other issues pertaining to estimates of the uninsured according to the CPS are discussed below.

The two principal classes of estimates of the uninsured using the CPS are (1) those done by the Census Bureau, CBO, GAO, and EBRI; and (2) those done by The Urban Institute. These estimates are summarized in Table II.1. The Urban Institute's estimates of the uninsured differ from the other estimates because they adjust for the underreporting of Medicaid in the CPS.