2005 National Hospital Ambulatory Medical Care Survey Data File
                          and File Documentation


                     WARNING - DATA USE RESTRICTIONS!
                       Read Carefully before Using

    The Public Health Service Act (Section 308 (d)) provides that the data
    collected by the National Center for Health Statistics (NCHS), Centers
    for Disease Control and Prevention (CDC), may be used only for the
    purpose of health statistical reporting and analysis.

    Any effort to determine the identity of any reported case is prohibited
    by this law.

    NCHS does all it can to assure that the identity of data subjects cannot
    be disclosed.  All direct identifiers, as well as any characteristics 
    that might lead to identification, are omitted from the dataset.  Any
    intentional identification or disclosure of a person or establishment
    violates the assurances of confidentiality given to the providers of the
    information.  Therefore, users will:

       1.  Use the data in this dataset for statistical reporting and
           analysis only.

       2.  Make no use of the identity of any person or establishment
           discovered inadvertently and advise the Director, NCHS, of any
           such discovery.

       3.  Not link this dataset with individually identifiable data from
           other NCHS or non-NCHS datasets.

    By using these data, you signify your agreement to comply with the 
    above-stated statutorily based requirements.
                      
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   The files listed below comprise the 2005 National Hospital Ambulatory 
   Medical Care Survey with complete file documentation.  
   
   The 2005 NHAMCS dataset includes two files, one for emergency department
   data and another for outpatient department data.  

   For ease of transmission, the data files have been converted into a self-
   extracting compressed format.  To load and expand the NHAMCS data files, 
   do the following: first, copy the compressed file onto your hard drive 
   into an appropriate folder (for example, NHAMCS).  Then doubleclick on 
   the file name from a Windows directory list, such as the Explore screen 
   (or go to the Command prompt in that folder and type the name of the 
   file [ED2005] without its extension). Do the same for the OPD2005 file. 
   New files will be created (with no extension) in the same folder, 
   which are uncompressed.  
   
   In the past, the NHAMCS documentation was produced in multiple files
   which were then compressed into a single self-extracting file in ASCII 
   format.  Beginning with 1999, the documentation file has been produced 
   as a single file in PDF format which can be viewed or downloaded from the 
   above address.  This file is not compressed.

                                                             Size (bytes)
   File Name         File Description                  Compressed  Uncompressed
  
   ED2005.EXE        NHAMCS Emergency department file      3.0 MB     28.5 MB
   OPD2005.EXE       NHAMCS Outpatient department file     2.1 MB     21.9 MB                                     

   DOC05.PDF         NHAMCS documentation file                         2.7 MB
   
   CAUTION - Because the NHAMCS is a sample survey, the application of 
   weights to the sample data is REQUIRED to produce national estimates
   of outpatient and emergency department visits, as well as to accurately 
   assess the sampling error of statistics based on the survey data.  Please 
   refer to the documentation for instructions on how to apply the weights 
   and to obtain relative standard errors of national estimates.
                                                   

   For questions, suggestions, or comments concerning NHAMCS data, please
   contact the Ambulatory Care Statistics Branch at (301) 458-4600.
   These and other survey data are also available on CD-ROM and public use
   data tape, as well as in published summaries.  For additional information
   on NCHS data products, contact the:

                   Office of Information Services, NCHS
                   3311 Toledo Road
                   Hyattsville, MD 20782
                   Tel: (301) 458-4636 
                   E-mail: nchsquery@cdc.gov
                   Internet: www.cdc.gov/nchs