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Ambulatory Health Care Data

Welcome NAMCS Participants

“Accurate data are essential for good decision-making. Your participation in the National Ambulatory Medical Care Survey will help us have the right information at the right time to help monitor and improve health care. This survey is vitally important, and we greatly appreciate and value your cooperation.” -- Thomas R. Frieden, M.D., M.P.H., Director, Centers for Disease Control and Prevention


Contact Information

If you have any questions or comments related to participation, please contact Don Cherry at:

Ambulatory and Hospital Care Statistics Branch
National Center for Health Statistics
3311 Toledo Road
Hyattsville, Maryland 20782
Phone: 800-392-2862
Fax: 301-458-4032

If you have questions about the survey that are not related to participation, please contact:

Ambulatory and Hospital Care Statistics Branch
National Center for Health Statistics
3311 Toledo Road
Hyattsville, Maryland 20782

Contact CDC-INFO


What is NAMCS?

The National Ambulatory Medical Care Survey (NAMCS) is the Nation’s foremost study of ambulatory care provided at physicians’ offices and has been conducted since 1973.  It focuses on visits made to non-federally employed office-based physicians who are primarily engaged in direct patient care.  Beginning in 2006, the survey also includes an annual sample of visits to community health centers (CHCs). NAMCS provides information on patient, provider, and visit characteristics. 

The annual NAMCS physician sample is composed of doctors of medicine (MDs) and doctors of osteopathy (DOs) representing an array of medical specialties.  Physicians are randomly selected based on information obtained from the masterfiles of the American Medical Association (AMA) and the American Osteopathic Association (AOA). The CHC sample is maintained by the Health Resources and Services Administration (HRSA).

Participants in NAMCS are asked to provide data on approximately 30 patient visits during a randomly assigned 1-week reporting period. These data are widely used by health care researchers, medical schools, policy analysts, congressional staff, the news media, and many others to improve our knowledge of medical practice patterns.  Since 2012, and continuing through 2013, the scope of NAMCS has expanded from a survey providing nationally representative estimates of visits to physician offices and CHCs to include visit estimates for some of the most populous U.S. states.

Reliable NAMCS data depend on complete reports from all sampled providers.  Data from all sampled visits are needed to ensure that policy decisions are based on the most accurate information possible.


Your participation is vital to the success of the survey

NAMCS Graphic - Your participation is important


NAMCS Participation

  • Who is eligible to participate?
    Nonfederally employed physicians (excluding those in the specialties of anesthesiology, radiology, and pathology) who are classified by the AMA or the AOA as primarily engaged in office-based patient care are randomly chosen to participate in NAMCS. Physicians and non-physician clinicians (i.e., physician assistants, nurse practitioners, nurse midwives) working at CHCs are also eligible to participate. Participation in NAMCS is completely voluntary.
  • Why participate?
  • NAMCS participation is important because without your contribution, neither you nor other health care providers like you can benefit from being represented in the national description of office-based and CHC patient care. You were randomly chosen to represent not only yourself but also thousands of other physicians and non-physician clinicians in your geographic region, state, and medical specialty.
  • What are the benefits of participating?

    By participating in NAMCS, you will be able to contribute to the national description of office-based and CHC-based patient care. Participation will result in more reliable data which will permit researchers, including other health care providers, to better assess the current state of ambulatory medical care utilization and provision.  NAMCS fulfills an ongoing need for national statistics on ambulatory care that can be used to improve professional education curricula for health care workers, formulate health policy, inform medical practice management, and evaluate quality of care. Failure to participate lessens the accuracy of data used by physicians and other researchers.

If you would like more information on participation, please contact Don Cherry at or (800)392-2862 or visit our Ambulatory Health Care Data home page.


2013 Highlights

NAMCS Computer Instrument

As in 2012, the 2013 NAMCS will be fielded as a fully computerized survey. The computerized survey instrument was tested throughout 2011 and made available to U.S. Census Bureau Field Representatives (our data collection agents) in November 2011 during a national training conference.  Use of the computerized survey instrument is expected to simplify data collection, reduce errors and omissions, and improve data quality. In addition, it will also reduce respondent burden by tailoring the data collection to each sampled visit, skipping irrelevant questions automatically.  Field Representatives (or interviewers, as they are also known) use laptops to enter information about physicians and non-physician clinicians during initial telephone screeners and induction interviews and also enter patient visit data for specified reporting periods.

NAMCS Sample Size

The 2013 NAMCS sample includes approximately 11,000 physicians from office-based settings and more than 6,000 CHC providers (which may include both physicians and non-physician clinicians).  As in 2012, NAMCS will continue sampling CHC providers at CHC service delivery sites, of which about 2,000 are included in the 2013 sample.

State-Based Estimates

The nearly five-fold sample increase from 2011 to 2012 (more than 21,000 physicians and CHC providers) will enable NAMCS to produce state-based estimates for the 34 most populous states in the U.S.  The 2013 NAMCS sample size will allow estimates to be made for the 22 most populous states.   For the first time, researchers will be able to use 2012 and 2013 NAMCS data to compare medical care for selected states with other states, with any of the 9 Census Divisions within the 4 Census Regions: Northeast (New England, Mid-Atlantic), Midwest (East North Central, West North Central), South (South Atlantic, East South Central, West South Central), and West (Mountain, and Pacific), and with the Nation.


NAMCS Initiatives

The 2013 NAMCS includes supplemental data on several medical topics. A Lookback Module will provide information on the clinical management of patients at risk for heart disease and stroke.  Physician workforce questions will collect data on the roles and responsibilities of non-physician clinicians and other medical staff in physician practices.  Current Procedural Terminology (CPT) codes for sampled visits will enable research on services rendered by various patient and visit attributes.  In addition, a data reabstraction study will help improve the quality of NAMCS data.  These are all described in more detail below.  

  • Lookback Module

    The intent of the Lookback module is to improve the nation’s ability to monitor and evaluate the quality of clinical care to prevent diseases such as heart disease and stroke. Sampled visits which indicate patients with elevated risk for heart disease or stroke will have additional information collected from all prior visits to that sampled provider during the past 12 months. For example, the module records medications prescribed, changes in medications, family history, contraindications to certain medications, and various laboratory tests (i.e., total cholesterol, HDL, LDL, TGS, HbA1c, FBG, and serum creatinine).  Combining data from the current visit as well as the prior visits will permit evaluation and monitoring of appropriateness of clinical management and the relationship to intermediate outcomes. Furthermore, information on the clinical management of such diseases could identify shortfalls in the quality of care and opportunities for improvement.  The same lab values collected on the Lookback module are also collected on the regular Patient Record form for the current sampled visit.

  • Physician Workforce
  • A set of questions examining physician workforce issues has been added to the 2013 NAMCS.  Fueled in part by changes in the delivery system, there is strong interest in understanding the dynamics of practice redesign and how team-based medical care is actually delivered.  A related interest is how advanced practice registered nurses (APRNs) and physician assistants (PAs) are utilized and whether they are used to the full extent of their licenses and training.  Adding questions to the NAMCS induction interview will provide a description of the composition of the practice team and the roles/responsibilities of its respective members for preventive services.  Issues to be explored might include the composition of the professional staff in the physician’s office, including whether it includes non-physician providers; and which staff, if any provide counseling, take vitals, etc. This exploration of provider types would go beyond physicians, APRNs and PAs, and could include registered nurses, community health workers, mental health providers, and others.  The expansion is sponsored by the Office of the Assistant Secretary for Planning and Evaluation (ASPE).

  • Current Procedural Terminology (CPT)
  • Historically, NAMCS has provided nationally representative data on the provision and use of ambulatory medical care services in physician offices and CHCs.  However, prior to 2013, data were not collected about the standard codes used by providers to describe these services. In order to increase the utility of NAMCS data for policy makers and researchers, NCHS has added a set of questions measuring the intensity of resources used during a visit.  Specifically, beginning in 2013, NAMCS collects up to 15 CPT codes associated with the services rendered during the visit to measure the relative costliness of providing such services.

  • Data Quality Control: Reabstraction
  • NAMCS currently relies on Census Bureau interviewers to abstract data from medical records and record it using the computerized survey instrument. The accuracy of our data is a top priority.  However, we understand the challenges that our data collection agents experience when completing abstractions. With this in mind, a new NAMCS initiative was developed in 2012, and will continue in 2013--reabstraction. 

    The purpose of reabstraction is to ensure data quality by quantifying the difference in collected information from two different interviewers. Reabstraction involves the use of a second independent senior-level interviewer who will return to the sampled participant’s reporting location and reabstract data from a limited number of cases. The second interviewer will follow the same NAMCS procedures for completing data abstractions.

    Once reabstraction is completed both sets of data undergo an item by item comparison used to identify any particular items with low agreement.  Reabstraction results may be used to design supplemental training in 2013 to improve abstraction quality, or may lead to proposed modification of instructions or data collection forms.


    NAMCS Supplements

    The inclusion of additional data supplements will allow researchers to focus on many research topics surrounding the use and adoption of electronic medical records/electronic health records systems.

  • Electronic Health Records/Electronic Medical Records (EHR/EMR) Mail Survey
  • In addition to the standard in-person NAMCS, a mail survey examining adoption of electronic health records (EMRs)/electronic medical records (EHRs) is being conducted again in 2013. The survey is being mailed to physicians who are otherwise eligible for NAMCS, but have not been selected in the regular NAMCS sample. The mail survey has been fielded continuously since 2008. The sample size was increased starting in 2010 so that state-level EMR/EHR estimates could be created.

    The mail survey is funded by the Office of the National Coordinator for Health Information Technology (ONC) and will assist in measuring the progress of the goal for most Americans to have access to an interoperable EHR by 2014. A report detailing findings from the 2012 mail survey is available as an NCHS Data Brief: Use and Characteristics of Electronic Health Record Systems Among Office-based Physician Practices: United States, 2001-2012.

  • Workflow Supplement
  • Added in 2011, the Physician Workflow Supplement is a longitudinal follow-up data collection initiative, also sponsored by ONC, to provide a better understanding of physician experiences with adoption and use of EHRs. The basesample for the survey comprises respondents to the 2011 EHR supplement. Respondents are being followed annually for a three-year period, beginning in 2011 and running through 2013. The main purpose of the survey is to obtain information on costs, benefits, and barriers related to the use of EHR systems at various stages of adoption.

    The Workflow Supplement data will help ONC and data users understand the experiences of adopters and measure progress towards Health Information Technology for Economic and Clinical Health Act (HITECH) program goals. Data will also help guide policymaking surrounding meaningful use criteria of EHR that have been established to help create a private and secure 21st century electronic health information system. Together with data from the EHR supplement, responses will help to develop criteria for successive stages of meaningful use. A report detailing the 2011 Physician Workflow Supplement is available as a NCHS Data Brief: Physician Adoption of Electronic Health record Systems: United States, 2011.


    Community Health Centers

    The 2013 NAMCS once again includes a sample of Community Health Centers. These were surveyed by NAMCS for the first time in 2006 and have been included in each annual survey since then.

  • What are Community Health Centers?

    Community Health Centers (CHCs) are local, non-profit, community-owned health care providers that serve low-income and medically underserved areas. Health centers serve as the medical home and family physician to over 20 million people nationally - a number that is quickly growing. Health center patients are among the nation's most vulnerable populations - people who even if insured would nonetheless remain isolated from traditional forms of medical care because of where they live, who they are, the language they speak, and their higher levels of complex health care needs. As a result, patients are disproportionately low income, uninsured or publicly insured, and minority.

  • Why include CHCs in NAMCS?

    Although general information is known about CHCs through the Uniform Data System (a mandatory reporting system within the Bureau of Primary Health Care, Health Resources and Services Administration), details of patient/physician encounters are not known.

    Visits made to CHCs, although in-scope for NAMCS, have been underrepresented in the survey because the normal sample of physicians is simply not large enough to capture many of the physicians who work at these important locations.

  • How does NAMCS sample CHCs?

    NAMCS includes three different types of CHCs in the sample: (1) CHCs that receive grant funds from the federal government through section 330 of the Public Service Act (PHSA), (2) Look-alike CHCs that meet all the requirements to receive 330 grant funding, but do not actually receive a grant, and (3) Urban Indian Federally Qualified Health Centers (FQHC).

    Up to three providers at each of the CHCs in the 2013 sample will be asked to participate. The resulting visits that are sampled from the providers will enable NCHS to provide separate statistics on the visits made to CHCs by selected states. Physicians, as well as non-physician clinicians (i.e., nurse practitioners, physician assistants, and nurse midwives) are all eligible participate in NAMCS as long as they meet selected requirements.


    Confidentiality and Privacy

    Confidentiality of NAMCS data

    NAMCS is conducted under the authority of Sec. 306 of the Public Health Service Act (42 USC 242k) which requires NCHS to collect statistics on a variety of health indicators. Information collected in this survey is used to study overall patterns of health care use by the population and for other similar statistical purposes. NCHS has a long history of protecting the privacy of information that we collect, and Sec. 308(d) of the Public Health Service Act (42 USC 242m) assures the confidentiality of data collected in the NAMCS. We strictly observe this confidentiality statute, which prohibits the release of identifiable information that we obtain unless we are given consent to do so by the subject.

    HIPAA Privacy Rule and NAMCS

    This section contains an overview of the Privacy Rule and how it affects your NAMCS participation.  For more comprehensive information on the Privacy Rule and the NAMCS, please go to HIPAA Privacy Rule Questions and Answers for NAMCS.

    The final Privacy Rule has been published as required by the Health Insurance Portability and Accountability Act of 1996 (HIPAA).  Health care providers who transmit financial and administrative health information electronically must comply with the Rule as of April 14, 2003.

    The Privacy Rule permits you to make disclosures of protected health information without patient authorization for public health purposes or for research that has been approved by an Institutional Review Board (IRB).  This survey meets both of these criteria. Additionally, disclosures may be made under a data use agreement [PDF - 1.1 MB] with NCHS.  If you have questions about your rights as a respondent, you may call the IRB at 1-800-223-8118.  The IRB is an independent board that protects the interests of people who take part in studies.  Click here to see the IRB approval letter [PDF - 3 MB] for NAMCS.

    We have included all the information you need to be assured that you are allowed to disclose protected health information for the NAMCS in our introductory letter to physicians [PDF - 18 KB], CHC directors [PDF - 18 KB], and CHC providers [PDF - 18 KB], and also here at our website.  However, there are several things that you must do to assure compliance with the Rule when participating in the survey. First, the privacy notice that you generally provide to your patients must indicate that patient information may be disclosed for either research or public health purposes.  And secondly, you may need to keep a record of the disclosure [PDF - 69 KB] (which we will provide) that shows that some data from the patient’s medical record were disclosed to CDC for the NAMCS. Of course, if you do not transmit health information electronically (such as claims data), then you are not subject to the Privacy Rule or the requirements described above.

    The Privacy Rule applies to data collected for the NAMCS because we are asking you to provide certain information about patients without their authorization.  For public health and research purposes, the NAMCS collects information from the patient's medical record such as visit date, birth date, and residential ZIP code.  While not directly identifiable, these data are considered protected health information as defined by the Privacy Rule.  As described above, the Rule allows you to disclose this information for public health and research purposes.

    In 2013, we will continue to collect the patient’s medical record number, which is considered directly identifiable information under the Privacy Rule.  The medical record number is used to assist the Census Bureau FRs during the abstraction process allowing them to (1) collect patient information from multiple sites within the clinic, (2) to identify the patient for correspondence with the office after the reporting period if the FR needs to update the patient information on any specific office visit, and (3) in the event that NCHS has to reabstract data for quality control (see above).  In general, the medical record number provides an opportunity for NCHS to check, confirm and verify the quality of the data the FR obtained via the abstraction process. If you are uncomfortable with providing the patient’s medical record number, simply request that this information be left blank on the computerized survey instrument.  If you do the data abstraction, simply leave the field blank.

    Please be assured that we fully intend to continue our long history of gaining the voluntary participation of providers like you by upholding the highest confidentiality standards and practices.

    For additional information on the confidentiality of NAMCS data, please go to NCHS’s Privacy Protection page and Frequently Asked Questions (FAQ’s) about the NAMCS. We also have a letter [PDF 33KB ] from the NCHS Confidentiality Officer explaining how HIPAA regulations allow you to participate in NAMCS.

    Your assurance of privacy

    NCHS is legally bound to assure confidentiality of all responses, including any information that might result in a physician’s practice or hospital being identified. The data files that are released for research do not include any provider or patient identifying information.

    NAMCS does not collect any personally identifiable data about patients such as patient's name or address; however, we do collect medical record number.  Although obtaining a patient’s medical record number is important for NAMCS, please note that it can easily be kept off the computerized survey instrument.  All information that may permit identification of an individual, a practice, or an establishment will be held confidential, will be used only by persons engaged in and for the purpose of the survey, and will not be disclosed or released to other persons or used for any other purpose without consent of the individual or the establishment in accordance with section 308(d) of the Public Health Service Act (42 USC 242m).

    To view the items included in the 2013 NAMCS Patient Record form, see NAMCS Survey Instruments.


    Data Utilization

    • How are NAMCS data used?
      NAMCS data are used to provide statistics that describe the characteristics of office visits to office-based physicians and CHCs. These include patient demographic characteristics, the conditions most often treated, and the diagnostic and therapeutic services rendered, including medication prescribed. These data are used by public health policy makers, health services researchers, medical schools, physician associations, epidemiologists, and the print and broadcast media to describe and understand the changes that occur in medical care requirements and practices. The data are disseminated in the form of public health reports, journal articles, and microdata files.


    NAMCS Data in the News

  • Nearly 40% of office-based physicians are using an electronic health record system with a basic level of functionality, according to an annual survey from CDC's National Center for Health Statistics, Modern Healthcare reports. (12/6/12), accessed 3/8/13.
  • Physicians May Overestimate EHR Capabilities: Three-quarters of doctors surveyed say their electronic health records systems can help them show Meaningful Use, but other polls challenge that optimistic view. Information Week Health Care (7/20/12), accessed 3/8/13.
  • NCHS Survey Shows Physicians Satisfied With EHR Technology: A national survey of office-based physicians reports that most of those who have adopted EHR systems are satisfied with the technology and say it has improved patient care. Advance for Health Information Professionals (7/18/12), accessed 3/8/13.

    Professional Endorsements

    This is truly a national resource. Without it, we would not have any reliable estimates of what happens at all the visits that Americans have with their doctors. -- Jim Rodgers, American Medical Association Vice president for Health Policy.

    NAMCS is endorsed by many professional organizations. Here is a list of organizational endorsements:

    • American Academy of Ambulatory Care Nursing
    • American Academy of Dermatology
    • American Academy of Family Physicians
    • American Academy of Neurology
    • American Academy of Ophthalmology
    • American Academy of Orthopedic Surgeons
    • American Academy of Otolaryngology – Head and Neck Surgery, Inc
    • American Academy of Pediatrics
    • American Academy of Physical Medicine and Rehabilitation
    • American College of Cardiology
    • American College of Obstetricians and Gynecologists
    • American College of Physicians
    • American College of Preventive Medicine
    • American College of Surgeons
    • American Osteopathic Association
    • American Psychiatric Association
    • American Society of Clinical Oncology
    • American Society of Plastic Surgeons
    • American Urological Association
    • Association of American Medical Colleges
    • National Association of Community Health Centers, INC.


    Continuing Medical Education for Health Care Providers

    Notice: The NAMCS Continuing Medical Education course is now available! The course entitled, “National Ambulatory Medical Care Survey Methods: What Clinicians Need to Know”, has been approved to offer 1.0 continuing medical education (CME) credit, 1.0 continuing nursing education (CNE) credit, and 0.1 continuing education (CEU) credit for physicians, nurses, and other health professionals who register for and complete the online module.


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