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eriu: Economic Research Initiative on the Uninsured Initiating and disemminating research to spark new policy discussion on health coverage issues.
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National Hospital Ambulatory Medical Care Survey (NHAMCS)

The National Hospital Ambulatory Medical Care Survey (NHAMCS) collects data on the use and provision of ambulatory care services in hospital emergency and outpatient departments. Findings are based on a national sample of visits to the emergency departments and outpatient departments of non-institutional general and short-stay hospitals, exclusive of Federal, military, and Veterans Administration hospitals, located in the 50 states and the District of Columbia. The survey uses a four-stage probability design with samples of geographically defined areas, hospitals within these areas, clinics within hospitals, and patient visits within clinics. Annual data collection began in 1992. The survey instrument is the Patient Record form, for which there are two versions; one for use in outpatient departments and another for use in emergency departments. Hospital staff are instructed to complete Patient Record forms for a systematic random sample of patient visits during a randomly assigned 4-week reporting period. Data are obtained on demographic characteristics of patients, expected source(s) of payment, patients' complaints, physicians' diagnoses, diagnostic/screening services, procedures, medication therapy, disposition, types of health care professionals seen, causes of injury where applicable, and certain characteristics of the hospital, such as type of ownership. A question pertaining to health insurance coverage is asked. The Primary Expected Source of Payment for a particular health visit is recorded. Categories include: Private insurance, Medicare, Medicaid, Worker's compensation, Self-pay, No charge, Other, and Unknown. Also, the survey records whether or not the patient belongs to an HMO.

Information about the NHAMCS can be found at