Survey
description
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, 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 with hospitals, and
patient visits within clinics.
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. Data are obtained on selected
demographic characteristics of the patients, clinical and other
characteristics of the visit, and certain characteristics of the hospital,
such as type of ownership.
Data
file description
The data set file for each
year contains two separate files--one for outpatient department visits and
another for emergency department visits. Each record on the file contains
a complete description of the ambulatory care visit, based on information
provided on the Patient Record forms. Additionally, each record contains
the statistical weight for inflating the sample visit to reflect annual
utilization of hospital outpatient departments or emergency departments in
the United States. Diagnosis, cause of injury, and procedure data are
coded using the International Classification of Diseases, Ninth Revision,
Clinical Modification (ICD-9-CM).
Patient's reason for visit and medications provided or prescribed are
coded using internal systems developed by the National Center for Health
Statistics.
Data
file technical characteristics
The following list describes the specific characteristics of each file for
each data year. Some of the CD-ROMs come with an ASCII format and some
comes with Statistical Export and Tabulation System (SETS)
retrieval software.
Data
year
Type
of
file
Number
of
records
2002
Emergency
dept.
37,337
Outpatient
dept.
35,586
2001
Emergency
dept.
34,546
Outpatient
dept.
33,567
2000
Emergency
dept.
25,622
Outpatient
dept.
27,510
1999
Emergency
dept.
21,103
Outpatient
dept.
29,487
1998
Emergency
dept.
24,175
Outpatient
dept.
29,402
1997
Emergency
dept.
22,209
Outpatient
dept.
30,107
1996
Emergency
dept.
21,902
Outpatient
dept.
29,806
1995
Emergency
dept.
21,886
Outpatient
dept.
28,393
1994
Emergency
dept.
26,547
Outpatient
dept.
29,095
1993
Emergency
dept.
29,117
Outpatient
dept.
28,357
1992
Emergency
dept.
36,271
Outpatient
dept.
35,114
Note: Each CD-ROM
contains two files, one for outpatient department data and one for
emergency department data.
Geographic
coverage
Data are available for the United States as a whole and for four
geographic regions.
Data
availability
The NHAMCS
began in 1992 and is conducted on an annual basis. Public use data files
are available for each survey year from 1992-2002 as downloadable ASCII
files from the Ambulatory Health Care Data website.
Data are also available on CD-ROM for each survey year. Data on CD-ROM are
accessed via Statistical Export and Tabulation Software (SETS) which comes
with the CD. Some years of data are also available on CD-ROM in ASCII
format.
Ordering
information SETS
CD-ROMs are available at no charge from NCHS or may be purchased from the
Government Printing Office (GPO)
when first released. ASCII data for individual years may
be purchased through the National Technical Information Service (NTIS).
As prices vary, please contact NTIS or GPO for current order numbers and
pricing. For availability, please check the listing of CD-ROM
and Video Products.
Documentation
contents
Complete documentation for each year of data is available
for downloading.
The CD-ROMs for each year contain complete electronic documentation for
the dataset and the SETS software.
Contact
Susan M. Schappert
Ambulatory Care Statistics Branch
Division of Health Care Statistics
3311 Toledo Road, Room 3409
Hyattsville, Maryland 20782
(301) 458-4480
E-mail: sds0@cdc.gov