organization, processes them into a uniform format, and then returns the uniform SID files to the statewide data organization. Beginning in 1988 with inpatient data from 8 hospitals, the NIS database has grown to cover 38 states in 2006. The NIS comes with weights that can be used to produce national, regional, and state estimates for participating states. See http://www.ahrq.gov/data/hcup/datahcup.htm for the complete list of databases that constitute the HCUP.
The Medical Expenditure Panel Survey (MEPS) collects data similar to those of its predecessor, the National Medical Expenditures Survey. Beginning in 1996 and repeated on an annual basis, the MEPS samples a portion of the households that participate in the prior year’s National Health Interview Survey. The household component of MEPS collects data continuously at both the person and household levels using an overlapping panel design. In 2002, approximately 18,000 households, consisting of nearly 40,000 individuals, were included in the survey. MEPS data are publicly available via download from the AHRQ website (see http://www.meps.ahrq.gov/mepsweb/).
Medicare claims are comprehensive medical claims records from 1991 through 2007 for about 50 million older Americans that are available to qualified entities from the Centers for Medicare & Medicaid Services (CMS). The files contain information on all Medicare-covered services (inpatient, hospital outpatient, ambulatory and physician care, durable medical equipment, home care, hospice care, skilled nursing care, rehabilitation care, etc.) and include information on diagnoses, treatments and procedures, discharge, Medicare and out-of-pocket expenditures, demographic characteristics, and managed care enrollment.
The Medicare Current Beneficiary Survey (MCBS), sponsored by CMS, is a nationally representative survey of aged, disabled, and institutionalized Medicare beneficiaries. Panelists are followed over the span of 4 years and are interviewed three times each year, regardless of whether they live in a household or a long-term care facility or switch between the two during the course of the survey period. The MCBS began in 1991; it is a patient-level comprehensive source of information on the health status, health care utilization, and expenditures of fee-for-service Medicare beneficiaries, health insurance coverage, and socioeconomic and demographic characteristics of the entire spectrum of Medicare beneficiaries. Self-reported utilization and expenditure information undergoes extensive validation using Medicare claims data. The cost and use data are available through 2006; data on access to care are available through 2008 at http://www.cms.gov/mcbs/.
The Medicare Denominator File, maintained by the University of Minnesota’s Research Data Assistance Center, contains demographic and enrollment information about each beneficiary enrolled in Medicare during a calendar year. Information contained in this file includes the beneficiary unique identifier, information on residence, date of birth, date of death, sex, race, and age. The files can be used to follow the vital status of the former respondents to the MCBS beyond