National Hospital Ambulatory Medical Care Survey, 2008 (ICPSR 29922)
Published: Jan 18, 2011
The National Hospital Ambulatory Medical Care Surveys (NHAMCS) provide data from samples of patient records selected from emergency departments (EDs) and outpatient departments (OPDs) of a national sample of hospitals. The resulting national estimates describe the use of hospital ambulatory medical care services in the United States. For the 2008 survey, data were colected from 209 OPDs and 431 EDs. Among the variables included are age, race, and sex of the patient, reason for the visit physician's diagnoses, cause of injury, surgical procedures (OPD's only), medication therapy, and expected source of payment. The 2008 survey remains unchanged from the previous year.
In preparing the data file for this collection, the National Center for Health Statistics (NCHS) has removed direct identifiers and characteristics that might lead to identification of data subjects. As an additional precaution, NCHS requires, under section 308(d) of the Public Health Service Act (42 U.S.C. 242m), that data collected by NCHS not be used for any purpose other than statistical analysis and reporting. NCHS further requires that analysts not use the data to learn the identity of any persons or establishments and that the director of NCHS be notified if any identities are inadvertently discovered. ICPSR member institutions and other users ordering data from ICPSR are expected to adhere to these restrictions.
Date of Collection
Data Collection Notes
The Stata datasets (.dta files) made available by ICPSR do not contain all of the value labels found within the .do files supplied by ICPSR. Specifically, the value labels that are composed primarily of ICD-9 codes have been omitted from the .dta files. Those data users interested in applying the value labels to the datasets will be able to edit the Stata setup files, which include the aforementioned labels, provided by ICPSR.
Per agreement with NCHS, ICPSR distributes the data file and text of the technical documentation for this collection as prepared by NCHS.
The National Hospital Ambulatory Medical Care Survey (NHAMCS) used a four-stage probability design with samples of primary sampling units (PSUs); hospitals within PSUs; clinics within hospitals; and patient visits within clinics.
Visits to the emergency and outpatient departments of noninstitutional general and short-stay hospitals within the 50 states and the District of Columbia, which had an average length of stay of less than 30 days, or to hospitals whose specialty was general (medical or surgical) or children's general. Excluded were federal hospitals, hospital units within institutions, and hospitals with less than six beds staffed for patient use.
Patient visit records from hospital emergency departments and outpatient departments.
administrative records data
Mode of Data Collection
90.2 percent unweighted, 89.8 percent weighted
Original Release Date
2011-01-18 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:
- Created variable labels and/or value labels.
- Created online analysis version with question text.
- Checked for undocumented or out-of-range codes.
Microdata file users should be fully aware of the importance of the "patient visit weight" (PATWT) and how it must be used. Information about the patient visit weight is presented in the codebook. If more information is needed, the staff of the Ambulatory Care Statistics Branch can be consulted by calling (301) 458-4600.
The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.
This study is maintained and distributed by the National Archive of Computerized Data on Aging (NACDA), the aging program within ICPSR. NACDA is sponsored by the National Institute on Aging (NIA) at the National Institutes of Heath (NIH).