National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS) Restricted Variables

The majority of NAMCS/NHAMCS variables are publicly available and researchers are highly encouraged to conduct preliminary analyses using these data. Researchers interested in accessing and/or conducting analyses using restricted NAMCS/NHAMCS variables must seek RDC approval. As part of the approval process, researchers are required to have a proposal approved by the RDC. Each proposal must include a data dictionary that describes the variables needed for analysis. Below is a list of the standard restricted variables. Please use this list when creating the data dictionary for your RDC Proposal.

NAMCS and NHAMCS Restricted Data [PDF – 37 KB]

If you are interested in using variables from NAMCS/NHAMCS that are not on the public files nor listed on the above file, please send an inquiry to In your email, include a list of questions from the survey instrument for which you were unable to find the corresponding variables. Proposals requesting these types of variables should not be submitted without first contacting

  • 2020 NAMCS Community Health Center (CHC) data are only available in the RDC.  The visit file can be used to make annual estimates. 2020 National Ambulatory Medical Care Survey–Community Health Centers Visit File Data Dictionary for Research Data Center Use (
  •  2020 NAMCS Provider File Data is only available in the RDC.  In addition to the standard physician file which can be used to make annual estimates, there is also a smaller file which covers Periods 3 and 4 from 2020 (when COVID-19 questions were added).  This file allows researchers to replicate data from the NAMCS COVID-19 Dashboard.  Data dictionaries for both files are available upon request.  Email with the subject “2020 NAMCS Provider File Data Dictionary Request”.
  • 2017 NAMCS Provider File Data is only available in the RDC. The 2017 NAMCS Provider File Data Dictionary is available upon request. Email with the Subject “2017 NAMCS Provider File Data Dictionary Request”.
  • Geocoded data for NAMCS and NHAMCS 1999-2009 are available at the NCHS Research Data Center. These data consist of distances between each patient’s ZIP Code of residence and the nearest hospital [PDF – 156 KB] and Federally Qualified Health Center [PDF – 136 KB]

Page last reviewed: January 19, 2022, 09:01 AM