and Quality (AHRQ) began fielding the Medical Expenditure Panel Survey (MEPS) on a continuing basis in March 1996. MEPS is conducted in conjunction with the National Center for Health Statistics (NCHS) and through contracts with Westat, a survey research firm headquartered in Washington, DC, and the National Opinion Research Center, which is affiliated with the University of Chicago. MEPS is a vital resource designed to continually provide policy makers, health care administrators, businesses, and others with timely, comprehensive information about health care use and costs in the United States and to improve the accuracy of their economic projections. MEPS collects data on the specific health services that are used, how frequently they are used, the cost of these services, and how they are paid for, as well as data on the cost, scope, and breadth of private health insurance held by and available to the U.S. population. For purposes of the current study, MEPS data have been combined for the period 1996-1999 to obtain a sample of 35,000 children.

MEPS Fact Sheet. February 2001. Agency for Healthcare Research and Quality, Rockville, MD. Additional information can be found at: http://www.meps.ahrq.gov/whatismeps/bulletin.htm.

National Health Interview Survey: The National Health Interview Survey (NHIS) is the principal source of information on the health of the civilian noninstitutionalized population of the United States and is one of the major data collection programs of the National Center for Health Statistics (NCHS). The National Health Survey Act of 1956 provided for a continuing survey and special studies to secure accurate and current statistical information on the amount, distribution, and effects of illness and disability in the United States and the services rendered for or because of such conditions. The survey referred to in the act, now called the National Health Interview Survey, was initiated in July 1957. Since 1960, the survey has been conducted by NCHS, which was formed when the National Health Survey and the National Vital Statistics Division were combined. NHIS data are used widely throughout the U.S. Department of Health and Human Services (DHHS) to monitor trends in illness and disability and to track progress toward achieving national health objectives. The data are also used by the public health research community for epidemiological and policy analysis, determining barriers to accessing and using appropriate health care, and evaluating federal health programs. The NHIS data for 2001 revealed that around 11 percent of children under the age of 18 lacked