Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

Ambulatory Health Care Data

Public Use Data File Updates

This page contains a list of updates that have been made to the NAMCS and NHAMCS public-use micro-data files and since their initial release dates. Data users can check here for any revisions that have been made to ensure that they are using the most accurate version of the files. For changes to the public-use micro-data file documentation (including general documentation and SAS, Stata, and SPSS programming code), please see Documentation Updates


2009 NHAMCS Emergency Department Public Use Data File and Documentation

9/20/11 – The 2009 NHAMCS Emergency Department Public Use File has been updated to include a change to the visit disposition variable ADMITHOS (admit to this hospital).  Original file data are correct, but it was discovered that some researchers were not aware that the disposition OBSHOS (admitted to observation unit, then hospitalized) should also be used to capture visits resulting in hospital admission.  To simplify matters, we have edited ADMITHOS to Yes whenever OBSHOS is Yes. Therefore, ADMITHOS will now reflect all visits resulting in hospital admission, either directly or through the observation unit.  A note regarding this change has also been added to the Public Use Data File Documentation.   Researchers using the original version of the file who are interested in hospital admissions need only select records where ADMITHOS is Yesor OBSHOS is Yes to capture all hospital admissions.


2004 NHAMCS Emergency Department File

8/4/06 - A slightly revised version of the 2004 NHAMCS Emergency Department file was uploaded to the ftp server. This file incorporates modifications to the edit process for the internal variables used to calculate WAITTIME (waiting time to see a physician) and LOV (length of visit). The revised WAITTIME and LOV are only minimally different than the first release, but have been made available in the interest of consistency with NCHS reports, the revised edit procedures, andfuture years of data which use those procedures.


2002 NHAMCS Emergency Department File

12/10/04 - We made revisions to two data items on the NHAMCS-Emergency Department public use file for 2002. These are ADRG2CL1 (1st NDC class for 2nd drug causing an adverse drug event) and DRG3ING5 (5th ingredient for 3rd medication provided or prescribed). Revisions were also made to one item on the NHAMCS-Outpatient Department file, EXAMWI2 (2nd write-in examination).


2002 NAMCS File (affects some SUDAAN users only)

9/29/04 - The 2002 NAMCS public use file was modified slightly to resolve a problem found when running SUDAAN version 8.0.2 and higher. This problem only appears when using the WOR (without replacement) design option with multi-level design variables and may cause the program to abort. For those using the SUDAAN WR (with replacement) option or other analytic software packages using an ultimate cluster model for variance estimation (for example, SAS, Stata, and SPSS), there should be no problem using the original version of the 2002 NAMCS public use file, so you do not need to replace your file with this new release.




National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey logos

Contact Us:
  • Ambulatory and Hospital Care Statistics Branch
    National Center for Health Statistics
    3311 Toledo Road
    Hyattsville, MD 20782
  • (301) 458-4600
  • Contact CDC–INFO The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #