National Hospital Ambulatory Medical Care Survey (NHAMCS)

The National Hospital Ambulatory Medical Care Survey (NHAMCS) is designed to collect data on the utilization 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 noninstitutional general and short-stay hospitals. 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.

Years Available: 1973-2004

Inclusion/Exclusion Criteria: Federal, military, and Veterans Administration hospitals excluded

Methods: Interview survey

Sampling Design: The survey uses a four-stage probability design with samples of geographically defined areas, hospitals within these areas, clinics within the outpatient departments and emergency service areas within the emergency departments of these hospitals, and patients visits to these clinics and emergency services areas. Specially trained interviewers visit the hospitals prior to their participation in the survey to explain survey procedures, verify eligibility, develop a sampling plan, and train hospital staff in data collection procedures. The survey instrument is the Patient Record form, which is provided in 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.

Sample Size: Approx. 71,000 annually.

Unit of Observation: Hospital visit

Limitations: About 8% of the encounter forms do not have race reported and 15% do not have ethnicity.

Data Format: SAS/SPSS

Publisher: CDC Center for Health Statistics

URL: http://www.cdc.gov/nchs/about/major/ahcd/ahcd1.htm#National%20Hospital%20Ambulatory%20Medical%20Care%20Survey%20(NHAMCS)

Variables: Data elements located here