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2003 National Healthcare Quality Report

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National Hospital Ambulatory Medical Care Survey (NHAMCS)


U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS).

Mode of Administration

Hospital staff are asked to complete one-page questionnaires (Patient Record forms) on a sample of their patient visits during an assigned reporting period.

Survey Sample Design

The NHAMCS utilizes a four-stage probability design that involves samples of primary sampling units (PSUs), hospitals within PSUs, clinics within hospitals, and patient visits within clinics. Hospital staff were asked to complete Patient Record forms for a systematic random sample of patient visits occurring during a randomly assigned 4-week reporting period during the survey year. Sample data are weighted to produce national estimates of patient visits. About 400 emergency departments participated in 1998 and more than 24,000 Patient Record forms were completed. About 230 outpatient departments (OPD) participated in 1998 and about 30,000 Patient Record forms were completed.

Primary Survey Content

NHAMCS includes two files: ED visits and OPD visits. Information is obtained on various aspects of patient visits, including patient characteristics, physician characteristics, and other visit characteristics. The survey form is redesigned every 2 years to address changing health data needs. Among the items collected are: patient's age, gender, race, and ethnicity; patient's expressed reason for visit; place, cause, work-relatedness, and intentionality of injury, if any; physician's diagnoses; diagnostic services ordered or provided; procedures provided; medications ordered, supplied, administered or continued; providers seen; visit disposition; immediacy with which patient should be seen; time spent with physician; and, expected source of payment.

Population Targeted

The basic sampling unit is the patient visit. Included in the survey are in-person visits by patients to EDs and OPDs of noninstitutional general and short-stay hospitals, exclusive of Federal, military, and Veterans Administration hospitals, located in the 50 states and the District of Columbia. Telephone contacts are excluded.

Demographic Data

Patient's age, gender, race, and ethnicity.

Years Collected

Annual since 1992.



Geographic Estimates

National, four U.S. Census Bureau regions.

Contact Information

Agency homepage:

Data system homepage:


Ly N, McCaig LF, National Hospital Ambulatory Medical Care Survey: 2000 Outpatient Data Summary. Advance data from vital and health statistics; No. 327. Hyattsville, MD: National Center for Health Statistics. 2002.

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