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 (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.  Beginning in 2006, the survey also includes an annual sample of visits to community health centers (CHCs). From 2012 through 2015, a new sampling design allowed NAMCS to make estimates not only for the nation and four Census regions but also for as many as 34 of the nation’s most populous 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 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.


NAMCS Highlights

NOTE: Current NAMCS Highlights, Initiatives and Supplements are shown below. Information for previous years is also available.

  • NAMCS Sample Size
    The 2017 NAMCS sample includes 3,000 physicians from office-based settings and approximately 300 CHC providers, which may include both physicians and non-physician clinicians, from 104 CHC delivery sites.
  • NAMCS Computer Instrument
    Since 2012, NAMCS has been a fully computerized survey. Field representatives (FRs) from the US Census Bureau (our data collection agent) 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.
  • State-Based Estimates
    From 2012-2015, the NAMCS sampling design allowed for the production of state-based estimates for a selection of states. In 2012, the 34 most populous states were targeted for estimation.  This number decreased each year in accordance with funding availability.  In 2013, 22 states were targeted; in 2014, the number was 18 and in 2015, the number was 17.  Starting in 2016, NAMCS returned to an area-based sampling design which permits estimates for the nation, nine Census divisions, and four Census regions.


NAMCS Initiatives

The 2017 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 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 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).
  • Sexually Transmitted Diseases Pre-Exposure Prophylaxis (STD PrEP)
    Starting in 2016, DHCS has collaborated with CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention to add 10 new questions to the Physician Induction Interview.  The new questions (labeled STD-PrEP) focus on policies, services, and experiences related to the prevention and treatment of sexually transmitted infections (STIs) and HIV prevention.  Issues include confidentiality for adolescent patients as well as current treatment methods for diagnosing and treating STIs in the same venue. Physicians are asked whether they undertake an HIV risk assessment with patients and whether their practice includes 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.  The STD-PrEP questions continue to be fielded in 2017.
  • Alcohol Screening and Brief Intervention
    Starting in 2015, DHCS has collaborated with CDC’s National Center on Birth Defects and Developmental Disabilities in support of their alcohol screening and brief intervention (SBI) initiative. The Center sponsors six questions on the Physician Induction Interview about alcohol SBI, and these questions are 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. NAMCS data will 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.  These questions continue to be asked in 2017.
  • 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 available as soon as resources will permit.
  • Laboratory Values
    NAMCS began collecting data on 6 laboratory tests at selected medical visits in 2010. Starting in 2013 and ongoing since then, NAMCS collects data on 7 laboratory tests (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.
  • 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 has continued each year since–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 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 and cultural competency.

  • Culturally and Linguistically Appropriate Services
    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.

Community Health Centers

The 2017 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 was 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 were not known. Visits made to CHCs, although in-scope for NAMCS, had been underrepresented in the survey prior to 2006 because the normal sample of physicians was 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 104 CHC delivery sites in the 2017 sample will be asked to participate. The resulting visits that are sampled from these providers will enable NCHS to provide separate statistics on visits made to CHCs. 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 certain requirements.  During 2012-2015, the sampling design of NAMCS allowed for CHC estimates to be made at the state level, in addition to national and regional estimates. Starting with the 2012 NAMCS, CHC data will be released independently of traditional NAMCS data, in files that contain data from physicians as well as non-physician clinicians.  Data from CHC providers can be combined with data from traditional NAMCS physicians.  The CHC data are currently being processed and release of the 2012 CHC data is expected this year.


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 icon[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.  In addition, NCHS complies with the Federal Cybersecurity Enhancement Act of 2015. This law requires the federal government to protect federal computer networks by using computer security programs to identify cybersecurity risks like hacking, internet attacks, and other security weaknesses. If information sent through government networks triggers a cyber threat indicator, the information may be intercepted and reviewed for cyber threats by computer network experts working for, or on behalf, of the government.

The Cybersecurity Act of 2015 permits monitoring information systems for the purpose of protecting a network from hacking, denial of service attacks and other security vulnerabilities.1 The software used for monitoring may scan information that is transiting, stored on, or processed by the system. If the information triggers a cyber threat indicator, the information may be intercepted and reviewed for cyber threats. The Cybersecurity Act specifies that the cyber threat indicator or defensive measure taken to remove the threat may be shared with others only after any information not directly related to a cybersecurity threat has been removed, including removal of personal information of a specific individual or information that identifies a specific individual. Monitoring under the Cybersecurity Act may be done by a system owner or another entity the system owner allows to monitor its network and operate defensive measures on its behalf.

1 “Monitor” means “to acquire, identify, or scan, or to possess, information that is stored on, processed by, or transiting an information system”; “information system” means “a discrete set of information resources organized for the collection, processing, maintenance, use, sharing, dissemination or disposition of information”; “cyber threat indicator” means “information that is necessary to describe or identify security vulnerabilities of an information system, enable the exploitation of a security vulnerability, or unauthorized remote access or use of an information system”.


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 icon[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 icon[PDF – 108 KB] 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 icon[PDF – 839 KB], CHC directors pdf icon[PDF – 919 KB], and CHC providers pdf icon[PDF – 919 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 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.

NAMCS does not collect any personally identifiable data about patients such as patient’s name or address.  In 2017, 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 by Census Bureau field representatives during the abstraction process to (1) collect patient information from multiple sites within the clinic, (2) identify the patient for correspondence with the office after the reporting period if the abstractor 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. 

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.

To view the items included in the 2017 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 Web Tables
  • Publications using NAMCS data


NAMCS Data in the News


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, Former Vice President for Health Policy, American Medical Association

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 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 Education Information

The NAMCS Continuing Medical Education course, titled “National Ambulatory Medical Care Survey (NAMCS): What Clinicians Need to Know” (WB2719), has been approved to offer 1.0 Certified in Public Health (CPH) recertification credit, 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. More information and instructions on how to access this online course can be found here.


Page last reviewed: April 29, 2019