National Hospital Discharge and Ambulatory Surgery Data
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National Hospital Discharge Survey Description

The National Hospital Discharge Survey (NHDS), which has been conducted annually since 1965, is a national probability survey designed to meet the need for information on characteristics of inpatients discharged from non-Federal short-stay hospitals in the United States. The NHDS collects data from a sample of approximately 270,000 inpatient records acquired from a national sample of about 500 hospitals. Only hospitals with an average length of stay of fewer than 30 days for all patients, general hospitals, or children’s general hospitals are included in the survey. Federal, military, and Department of Veterans Affairs hospitals, as well as hospital units of institutions (such as prison hospitals), and hospitals with fewer than six beds staffed for patient use, are excluded.

Beginning in 1985, two data collection procedures have been used in the survey. One is a manual system in which sample selection and medical transcription from the hospital records to abstract forms is performed by the hospital’s staff or by staff of the U.S. Bureau of the Census on behalf of NCHS. The other data collection procedure is an automated system in which NCHS purchases machine-readable medical record data from commercial organizations, State data systems, hospitals, or hospital associations. The medical abstract form and the automated data tapes contain items that relate to the personal characteristics of the patient. These items include age, sex, race, ethnicity, marital status, and expected sources of payment. Administrative items such as admission and discharge dates (which allow calculation of length of stay), as well as discharge status are also included. Medical information about patients includes diagnoses and procedures coded to the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). A detailed description of the NHDS is included in "Design and Operation of the National Hospital Discharge Survey: 1988 Redesign," Vital and Health Statistics, Series 1, Number 39.
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Data from the NHDS are available annually and are used to examine important topics of interest in public health and for a variety of activities by governmental, scientific, academic, and commercial institutions. National Hospital Discharge Survey data are available in publications, on public-use data tapes, data diskettes, CD-ROMs and downloadable files from the FTP server.