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National Hospital Discharge Survey (NHDS) Public-use Data Files

Survey description
Data file description
List of data file variables at a glance
Data file technical characteristics
Geographic coverage
Data availability
Ordering information
Documentation contents
Related reports
Contact
NHDS web page

Survey description
The National Hospital Discharge Survey (NHDS) is a continuous nationwide survey of inpatient utilization of short-stay hospitals. Survey data are abstracted from sampled medical records of inpatients discharged from a national sample of non-Federal short-stay hospitals.

Data file description
Separate files are prepared for each annual survey. Each file contains approximately 200,000 records that have a fixed-length format. Beginning in 1993, the layout of the public-use files was changed to be compatible with that of the multiyear files. This was done to allow for easily concatenating the annual files after 1993 with the multiyear files.

A set of multiyear files with data for the 1979 to 1997 data years, combined and reformatted with standard coding of all variables, is also available. Unlike the single year files, the multiyear files separate records for newborn infants and non-newborns as distinct data files.

NHDS data on diskettes are intended as an information source for researchers and other who need data for detailed diagnostic procedures and diagnosis-related group (DRG) categories but do not need the record-level detail provided by the complete public-use data file.

List of data file variables at a glance

Patient data
Age at date of admission
Sex
Race
Marital status
Expected source of payment (1977-97)
Data of admission (month, day, year). (Admission
month only for 1993-97 and multiyear files)
Date of discharge (month, day, year) (Omitted on
1993-97 and multiyear files)
Discharge status

Diagnostic and procedure codes
Diagnostic codes (1970-78: one to five 4-digit
ICDA-8 diagnostic codes: 1979-97; one to seven
5-digit ICD-9-CM codes)
Diagnosis-related group (DRG) codes: 1986-97
(Not on multiyear file.)
Procedure codes (1970-78: zero to three 3-digit
ICDA-8 procedure codes: 1979-97: zero to four
4-digit ICD-9-CM procedure codes)
Dates of procedures, if procedure codes are not zero
(1979-92: one to four; month, day year)
This data item is not available on the 1993-97
files or on the multiyear file. ICD-9-CM codes)
Diagnosis-related group (DRG) codes: 1986-97
(Not on multiyear file.)
Procedure codes (1970-78: zero to three 3-digit
ICDA-8 procedure codes: 1979-97: zero to four
4-digit ICD-9-CM procedure codes)
Dates of procedures, if procedure codes are not zero
(1979-92: one to four; month, day year)
This data item is not available on the 1993-97
files or on the multiyear file.

Hospital data
Bed size of hospital
Ownership of hospital
Length of stay in days
Weight (final adjusted weight for each sample record)
Geographic region of hospital

Data file technical characteristics
The following list describes the specific characteristics of each file for each data year. The CD-ROM format comes with the Statistical Export and Tabulation System (SETS) retrieval software. Data on diskettes are a complete package and include software for accessing the database files, for computing rates of selected populations, and for creating subfiles for use with other software packages. (SETS) retrieval software. Data on diskettes are a complete package and include software for accessing the database files, for computing rates of selected populations, and for creating subfiles for use with other software packages.

The multiyear CD-ROM files, which cover the years 1979 to 1996, have 3,778,368 non-newborn records and 422,512 newborn records.

Geographic coverage
The NHDS is a nationwide survey that allows analysis at the U.S. Bureau of the Census region level (division level before 1988).

Data availability
Hospital utilization data are collected annually. Data are available for individual years from 1970-97.   The multi-year file contains data from 1979-97 and is available on CD-ROM. Data diskettes are available from 1985-94.

Ordering information
The NHDS ASCII CD-ROM and diskettes can be purchased through the National Technical Information Service (NTIS). The SETS CD-ROMs can be purchased from NTIS and the Government Printing Office (GPO). Please contact NTIS and GPO for the most current prices.  The NTIS and GPO order numbers are as follows:

Data on CD-ROM - ASCII

Data on diskette -  ASCII

Data on CD-ROM - SETS

Multi-year data on CD-ROM - SETS

Documentation content
Each NHDS product contains the necessary documentation, including content and technical information, needed to access the data. Documentation is available electronically on the CD-ROM and documentation for the diskettes are included in the software package.

Related reports
Reports that relate to the data and sample design are available in Vital and Health Statistics, Series 2 and 13. Data are also published in the Advance Data series.

Contact
Hospital Care Statistics Branch
Division of Health Care Statistics
National Center for Health Statistics
Centers for Disease Control and Prevention
3311 Toledo Road, Room 3409
Hyattsville, Maryland 20782
(301) 458-4321

This page last reviewed January 11, 2007