Ambulatory Health Care Data

Welcome NAMCS Participants

The National Health Care Surveys (including NAMCS, NHAMCS, and NHCS) are working with the Centers for Medicare and Medicaid Services Electronic Health Record Incentive Programs: Promoting Interoperability (PI) (formerly known as Meaningful Use, or MU) and the Merit-based Incentive Payment System (MIPS). Click here to find out more.


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.  Since 2006, the survey has also included an annual sample of visits to community health centers (CHCs). From 2012 through 2015, a new sampling design allowed NAMCS to make estimates for the nation, nine U.S. Census divisions, four U.S. Census regions, and depending on the year, a select number of individual US states. 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.

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 advanced practice providers (i.e., physician assistants, nurse practitioners, and 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 advanced practice providers in your geographic region, state, and medical specialty.
  • What types of CHCs and CHC providers participate?
    Three different types of CHCs are eligible for participation in NAMCS: (1) CHCs that receive grant funds from the federal government through section 330 of the Public Health 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 CHC delivery site are asked to participate. Physicians and advanced practice providers (i.e., nurse practitioners, physician assistants, and nurse midwives) are all eligible to participate in NAMCS, as long as they meet certain requirements.
  • 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.
  • How does the process work?
    Physicians and CHC service delivery sites are chosen through a random selection process. Letters informing physicians or CHC directors about the purpose of the study are sent first. Then, within two weeks of the physician’s or CHC’s earliest induction date, the physician or CHC director is typically contacted over the phone by a U.S. Census Bureau field representative (FR) who confirms that the physician or CHC site is eligible for participation. Sometimes this initial contact happens in person. Once confirmed as eligible, the FR will conduct an induction interview (usually in-person) with (a) the physician to determine the volume of office visits and collect various office characteristics, or (b) the CHC Director to help determine which physicians or advanced practice providers (i.e., physician assistants, nurse practitioners, and nurse midwives) at the CHC will be interviewed and asked to provide visit data. Once these induction interviews are complete, and the different providers are determined to be eligible, the FRs then visit the offices or CHCs, abstracting medical data from a sample of visits occurring during the predetermined sample week.

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.


Confidentiality and Privacy

Confidentiality of NAMCS data

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

We take your privacy very seriously.  All information that relates to or describes identifiable characteristics of individuals, a practice, or an establishment will be used only for statistical purposes. NCHS staff, contractors, and agents will not disclose or release responses in identifiable form without the consent of the individual or establishment in accordance with section 308(d) of the Public Health Service Act (42 USC 242m)external icon and the Confidential Information Protection and Statistical Efficiency Act of 2002 (CIPSEA, Title 5 of Public Law 107-347) [PDF – 51 KB]external icon. In accordance with CIPSEA, every NCHS employee, contractor, and agent has taken an oath and is subject to a jail term of up to five years, a fine of up to $250,000, or both if he or she willfully discloses ANY identifiable information about you.


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 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 have been required to comply with the Rule since 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 the NCHS Ethics Review Board (ERB).  This survey meets both of these criteria. Additionally, disclosures may be made under a data use agreement pdf icon[PDF – 1.1 MB] with NCHS.  If you have questions about your rights as a respondent, you may call the ERB at 1-800-223-8118.  The ERB is an independent board that protects the interests of people who take part in studies.  Click here to see the ERB approval letter pdf icon[PDF – 77 KB] for NAMCS.

We have included all the information you need to be assured that you are allowed to disclose protected health information for NAMCS in our introductory letter to introductory letter to physicians pdf icon[PDF – 839 KB], CHC directors pdf icon[PDF – 919 KB], and CHC providers pdf icon[PDF – 248 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 icon[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 NAMCS because we are asking you to provide certain information about patients without their authorization.  For public health and research purposes, 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.

For additional information on the confidentiality of NAMCS data, please go to NCHS’s Privacy Protection page and Frequently Asked Questions (FAQ’s) about NAMCS.


Data Utilization

  • How are NAMCS data used?
    NAMCS data are currently used to provide statistics that describe the characteristics of visits to physician offices and CHCs. The data elements include patient demographic characteristics; the conditions most often treated; and the diagnostic and therapeutic services rendered, including medications prescribed. These data are used by the U.S. Congress and other public health policy makers, government agencies, universities and medical schools, professional associations, health services researchers and epidemiologists, as well as the print, broadcast, and web media to describe and understand the changes that occur in medical practice. The data are disseminated in the form of government reports, journal articles, and microdata files.


NAMCS Data in the News


NAMCS Survey Results and Products

NCHS publishes a number of web tables, reports, and factsheets using NAMCS data. A list of all these available products can be found here.

Professional Endorsements

A number of professional organizations have formally endorsed NAMCS, including:

  • 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 Otolaryngology – Head and Neck Surgery
  • 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
  • National Association of Community Health Centers


NAMCS Data Supplements and Initiatives

Current Data Supplements and Initiatives

The 2019 NAMCS continues to include data collection on certain items of special interest to health policy researchers:

  • Physician Workforce
    The physician workforce question set was first added to the NAMCS Physician Induction Interview in 2013 and has been continued every year since.  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.  The NAMCS workforce questions 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 advanced practice 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) codes
    In 2013, NAMCS began collecting CPT codes associated with the services rendered during the medical visit to measure the relative costliness of providing such services.  This effort has continued each year since then.  CPT code data have not yet been released, in part because of the additional data processing required with this new effort.  Plans are underway to assess the data with the goal of making it publicly-available as soon as resources will permit.
  • Laboratory Values
    NAMCS began collecting data on six laboratory tests at selected medical visits in 2010. Since 2013, NAMCS has collected data on seven laboratory tests (i.e., total cholesterol, high density lipoprotein, low density lipoprotein, triglycerides, glycohemoglobin, fasting blood glucose, and serum creatinine). The American Heart Association recommends collecting such data in order to track progress in meeting national goals for the prevention and management of heart disease and stroke. The lab values collected represent tests commonly ordered to monitor cardiovascular fitness, and diabetes detection and management.
  • National Electronic Health Records Survey
    Since 2008, NAMCS has included a data supplement to allow researchers to focus on the use, adoption, and interoperability of electronic medical records (EMRs)/electronic health records (EHRs):
  • National Electronic Health Records Survey (NEHRS) is an annual, nationally representative survey of office-based physicians that collects information on physicians’ EHR systems and other physician and practice characteristics.  It was originally designed in 2008 as a mail supplement to the National Ambulatory Medical Care Survey (NAMCS), and was expanded to make state-based estimates in 2010.  Starting in 2012 NEHRS has been a stand-alone survey.  The most recent year of NEHRS data available is 2017.

Previous Data Supplements and Initiatives

  • Sexually Transmitted Diseases Pre-Exposure Prophylaxis (STD PrEP)
    From 2016 through 2018, NCHS collaborated with CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention to add ten questions to NAMCS.  The new questions (labeled STD-PrEP) focused on policies, services, and experiences related to the prevention and treatment of sexually transmitted infections (STIs) and HIV prevention.  The questions collected data on issues such as confidentiality for adolescent patients as well as current treatment methods for diagnosing and treating STIs in the same venue. Physicians were asked whether they undertook an HIV risk assessment with patients and whether their practice included high-risk patients. A risk assessment is important for all persons, which is why these questions cover a wide range of sexual and drug-use behaviors. These questions were drawn from a panel of experts familiar with the CDC STD Treatment Guidelines and recommendations from several studies on sexual behaviors and STDs.
  • Alcohol Screening and Brief Intervention
    From 2015 through 2018, NCHS collaborated with CDC’s National Center on Birth Defects and Developmental Disabilities (NCBDDD) in support of their alcohol screening and brief intervention (SBI) initiative. NCBDDD sponsored six questions on NAMCS about alcohol SBI, and these questions were asked only of primary care providers. It is imperative to survey primary care providers to determine the extent to which alcohol SBI is being conducted within their practices. These data can be used to (1) learn the extent to which alcohol SBI is conducted among primary care providers, (2) gain insight on the type(s) of alcohol screening instruments used, administration methods employed, and staff type(s) responsible for conducting alcohol SBI within the primary care setting, and (3) assess the types of resources primary care providers would find helpful for implementing alcohol/substance SBI in their setting.
  • Culturally and Linguistically Appropriate Services
    In 2016 the National Ambulatory Medical Care Survey (NAMCS) Supplement on Culturally and Linguistically Appropriate Services for Office-based Physicians (National CLAS Physician Survey) examined cultural and linguistic competency, provision, training and awareness among office-based physicians. It was a mixed mode survey fielded to 2,400 physicians who were otherwise eligible for NAMCS, but had not been selected in the regular NAMCS sample. The National CLAS Physician Survey was funded by the Office of Minority Health (OMH), Office of the Secretary, Department of Health and Human Services. The survey can provide national and regional estimates. National CLAS Physician Survey data collection was August through December 2016. The data are now available.


Page last reviewed: June 13, 2021