Welcome NHAMCS Participants
“Accurate data are essential for good decision-making. Your participation in the National Hospital 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
If you have any questions or comments related to participation, please contact Farida Bhuiya at:
Ambulatory and Hospital Care Statistics Branch
National Center for Health Statistics
3311 Toledo Road
Hyattsville, Maryland 20782
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
The National Hospital Ambulatory Medical Care Survey (NHAMCS) is the Nation’s foremost study of ambulatory medical care in hospital emergency and outpatient departments and has been conducted annually since 1992.
Each year, approximately 500 nationally representative hospitals provide data on a sample of patient visits to selected outpatient clinics, emergency service areas, and, since 2009, ambulatory surgery locations. About 200 freestanding ambulatory surgery centers have provided data since 2010 on a sample of ambulatory surgery visits. Sample data are collected over a 4-week reporting period which varies by facility.
These data are widely used by health care researchers, policy analysts, congressional staff, the news media, and many others to improve our knowledge of medical practice patterns.
Reliable NHAMCS data depend on complete reports from all sampled hospitals. Data from all sample cases are needed to ensure that policy decisions are based on the most accurate data possible.
Who is eligible to participate?
Non-Federal general and short-stay hospitals, located in the 50 States and the District of Columbia, that have a 24-hour ED, an OPD with physician services clinics, or a hospital-based ambulatory surgery center, are eligible to be sampled in the hospital component of NHAMCS.
Freestanding ambulatory surgery centers located in the 50 States and the District of Columbia that are regulated by states or certified by the Centers for Medicare and Medicaid Services are eligible to be sampled in the freestanding ambulatory surgery center component of NHAMCS. Participation in the NHAMCS is voluntary.
NHAMCS participation is important because without it, neither your hospital or freestanding ambulatory surgery center nor others like yours can benefit from being represented in the national description of visits to outpatient departments, emergency departments, and ambulatory surgery centers. Your facility was randomly chosen to provide representative data not only for its own outpatient clinics, emergency service areas, and ambulatory surgery locations, but also for similar hospitals or freestanding ambulatory surgery centers in the same geographic region.
Furthermore, the September 11, 2001, attack on our nation and subsequent bioterrorism incidents have highlighted the unique role of the emergency department within the health care system. In addition to being a "safety net" provider, the emergency department must be able to respond to bioterrorism and mass casualty incidents, natural disasters, and pandemics; therefore, it is important to collect data from this setting.
What are the benefits of participating?
By participating in the NHAMCS, you will be able to contribute to the national description of hospital-based ambulatory care and/or the growth in ambulatory surgery. The need for more complete ambulatory medical care data has been accentuated by recent efforts towards health care reform, the rapidly aging population, the growing number of persons without health insurance, emergency department crowding, the introduction of new medical technologies, and the shift from hospital inpatient to outpatient surgery. Your hospital's or freestanding ambulatory surgery center's participation will result in more reliable statistics and will enable researchers to better measure the utilization and provision of ambulatory health services. Failure to participate lessens the accuracy of the data used by researchers.
NHAMCS Automated Computer Instrument
Starting in January 2012, the NHAMCS will be fielded using an automated computer instrument. Use of a computerized instrument is expected to simplify data collection, reduce errors and omissions, and improve data quality. The instrument was pre-tested in April 2011 and utilized by U.S. Census Bureau Field Representatives (the NHAMCS data collection agents) in November 2011 during a national NHAMCS training conference. Survey Field Representatives will enter information from hospital staff into the computerized instrument during the initial telephone screener and induction interviews and will also enter patient visit data for the specified reporting period.
Outpatient Department 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 the clinic during the past 12 months. 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 National Survey of Ambulatory Surgery (NSAS) was conducted by the National Center for Health Statistics in 1994-96 and again in 2006. Because of the shift from hospital inpatient to outpatient surgery for many procedures, it is important to collect these data annually; therefore, the NSAS has been incorporated into the NHAMCS. Beginning in 2009, hospital-based ambulatory surgery centers were included in the study and, in 2010, freestanding ambulatory surgery centers were included. Data from the 2009 survey of hospital-based ambulatory surgery centers are expected to be available in 2011.
Confidentiality of NHAMCS data
The NHAMCS 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 NHAMCS. 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. In addition, provisions of the Confidential Information Protection and Statistical Efficiency Act of 2002 (Title V of PL 107-347) [PDF - 51 KB] provide for a felony conviction and/or fine of up to $250,000 if this promise is violated.
This section contains an overview of the Privacy Rule and how it affects your NHAMCS participation. For more comprehensive information on the Privacy Rule and the NHAMCS, please go to HIPAA Privacy Rule Questions and Answers for NHAMCS.
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 your facility 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 - 26 KB] with NCHS. If you have questions about your facility’s 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 NHAMCS.
We have included all the information you need to be assured that your facility is allowed to disclose protected health information for the NHAMCS in our introductory letters [PDF - 176 KB] to hospitals and freestanding ambulatory surgery centers 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 your facility generally provides to patients must indicate that patient information maybe disclosed for either research or public health purposes. And, secondly, your facility may need to keep a record of the disclosure [PDF - 17 KB] (which we will provide) that shows that some data from the patient’s medical record were disclosed to CDC for the NHAMCS. Of course, if your facility does not transmit health information electronically (such as claims data), then it is not subject to the Privacy Rule or the requirements described above.
The Privacy Rule applies to data collected for the NHAMCS because we are asking you to provide certain information about patients without their authorization. For public health and research purposes, the NHAMCS 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.
Please be assured that we fully intend to continue our long history of gaining the voluntary participation of hospitals and freestanding ambulatory surgery centers like yours by upholding the highest confidentiality standards and practices.
Your assurance of privacy
NCHS is legally bound to assure confidentiality of all responses, including any information that might result in a hospital or freestanding ambulatory surgery center being identified. The data files that are released for research do not include any provider or patient identifying information.
The NHAMCS does not collect any personally identifiable data about patients such as patient's name or address. The top section of the NHAMCS Patient Record form, the survey instrument, contains a detachable section where facility staff can record the patient's name for reference purposes. This section is detached prior to submission of the forms, and is kept by facility staff for several weeks, in case it is necessary to retrieve missing information or clarify recorded information. Other 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).
Patient Record Forms
To see a copy of the NHAMCS Emergency Department and Outpatient Department and Ambulatory Surgery Patient Record forms, NHAMCS Survey Instruments.
The following supplement was used from 2006-2010:
In 2006, CDC's National Center for Health Statistics and National Center for Chronic Disease Prevention and Health Promotion joined forces to collect information on the screening of cervical cancer at hospital-based outpatient departments in the United States.
Genital human papillomavirus (HPV) infection is common among sexually active populations. At the start of the supplement, there was considerable new information about HPV infection, transmission, and methods of prevention. In addition, a new DNA test to detect HPV as well as newly approved indications for HPV testing were seen as having important implications for clinicians in both their cervical cancer screening practices and their management of positive HPV diagnoses among female patients and their sex partners. There was recognition that this new information might require different approaches to cervical cancer screening in primary care practice, as well as new information that needed to be conveyed when counseling and educating patients and their sex partners.
The Cervical Cancer Screening Supplement was a self-administered 4-page questionnaire given to medical directors of general medicine and obstetric-gynecology clinics that performed cervical cancer screening. The content included questions about screening methods for cervical cancer, including ordering HPV DNA tests, and administration of the HPV vaccine.
The following supplement was used in 2008:
The Pandemic and Emergency Response Preparedness Supplement was added to the 2008 NHAMCS at the request of the Office of the Assistant Secretary for Planning and Evaluation (OASPE) of the Department of Health and Human Services (DHHS). Information was obtained on the content of the hospital’s emergency response plan, staff training, participation in mass casualty drills, and the hospital’s resources and capabilities.
The questionnaire was adapted from a previous NHAMCS supplement on Bioterrorism and Mass Casualty Preparedness that was fielded in 2003 and 2004. Certain elements (such as existence of updated emergency response plans) remained the same in order to be able to establish trends over time. Other elements were revised to answer questions generated by the previous surveys and newer public health priorities. Examples include adding infectious diseases such as influenza and severe acute respiratory syndrome (SARS), expanding the categories for chemical and radiological exposures to include specific agents targeted in the hospital preparedness grant guidances, and adding specificity on some resources such as decontamination showers, to include numbers of patients able to be accommodated.
The content included questions about evacuation plans and the set-up of temporary facilities should the hospital not be able to operate. Supplement data will be used to assess progress towards hospital preparedness for dealing with bioterrorism and mass casualty incidents, and in so doing evaluate the ability of hospitals to deal with naturally occurring diseases, epidemics and pandemics, such as SARS or influenza. This project supports the DHHS goal to prepare for emerging health threats. The project also provides nationally representative benchmarks that can serve as one quality control mechanism for other projects that are designed to detect emerging health threats within a shorter time period.
The following supplement was used in 2002, 2003, and 2006:
The Emergency Pediatric Services and Equipment Supplement (EPSES) was first used in 2002 and 2003 and reintroduced in 2006. It was sponsored by the Health Resources and Services Administration (HRSA) and assessed how well hospitals were prepared to provide emergency pediatric services. NCHS is using the data collected to evaluate emergency pediatric preparedness at a national level. This is NOT an assessment or evaluation of individual hospitals. This is a study to produce data for national statistics on pediatric preparedness in hospital ED settings.
The following four supplements were used in 2003 and 2004.
Because hospital personnel frequently report that the chief reason for ED crowding is the lack of inpatient beds, it is important to obtain inpatient bed counts. Comparing the number of licensed and staffed beds on the Hospital Capacity Card will provide an indication of untapped capacity. NCHS would like to do a comparison of the daily inpatient occupancy rate with the frequency of ambulance diversion.
The purpose of this supplement is to obtain data on issues related to ED crowding. It is important to know if the ED performs triage, how many treatment spaces there are, specific information about physician staffing, and the availability of on-all specialists. NCHS would like to know the training level of physicians working in the ED in order to assess how it accounts for variation across EDs in observed treatment patterns.
The purpose of the Ambulance Diversion Log is to obtain data on ambulance diversion. There are no national estimates available on diversion frequency and no information comparing types of cases seen in EDs while they are on diversion. In order to help policymakers, NCHS would like to know in what proportion of hospitals diversion occurs and with what frequency; the reasons for the diversion; and who in the hospital ordered the diversion.
There is a growing appreciation of the unique role of the ED within the US health care system and of its expanding role as a “safety net” provider. The attacks on September 11, 2001, and the subsequent cases of anthrax spotlight the quintessential role of EDs in the immediate response to mass casualty incidents and in the detection and surveillance of bioterror-related diseases. To improve their preparedness for biological and chemical attacks, hospitals face clinical and communications challenges. One of the biggest obstacles to a hospital’s readiness is recognizing the early signs of a terrorism-related condition, because many biochemical agents trigger routine symptoms in patients. This is a self-administered two-page questionnaire pertaining to the hospital’s preparedness for events involving bioterrorism and mass casualties. It includes questions on additional training received on this topic since September 11, 2001.
How are NHAMCS data used?
NHAMCS data are currently used to provide statistics that describe the characteristics of visits to hospital emergency departments and outpatient departments. In the future, statistics also will be produced on procedures performed at both hospital-based and freestanding ambulatory surgery centers. The data elements include patient demographic characteristics; the conditions most often treated; and the diagnostic and therapeutic services rendered, including medication 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
- NHAMCS data in the news
- "One-quarter of acute care doctor visits take place in ERs" (see article, “Health Care Wastefulness Is Detailed in Studies”) --New York Times, 9/7/10.
- "ER visits for adominal pain up, chest pain down"--USA Today, 9/8/2010.
- ED Physicians Test Few Infants and Toddlers for UTI: Emergency department (ED) physicians were more likely to order blood tests for infants and toddlers with unexplained fever than they were to order tests for urinary tract infections (UTIs), despite longstanding recognition that UTIs should be considered in any young child with an unspecified fever, reveals a study published online November 21 in Pediatrics. Medscape Medical News, 11/22/2011.
- Kids’ ER visits for psychiatric care inching up: Emergency room doctors are seeing more and more kids for mental health problems, and many of them are uninsured, researchers said at the annual conference of the American Academy of Pediatrics in Boston. Reuters, 10/24/2011.
- Too many kids getting antibiotics for asthma: Although guidelines don't recommend antibiotics for asthma, almost 1 million children with the respiratory condition are prescribed the medications each year in the United States, a new study finds. USA Today, 5/20/2011.
- NHAMCS Charts and Tables
- Outpatient Department Visit Data
- Emergency Department Visit Data
- Publications using NHAMCS data
"NHAMCS is an invaluable resource for anyone who wants to understand critical issues about access to care, utilization of hospital emergency departments, and other matters of fundamental importance to the health of Americans." -- Art Kellermann, MD, MPH, FACEP, Paul O’Neill-Alcoa Chair in Policy Analysis, RAND Corporation; Former Professor and Chairman, Department of Emergency Medicine, Emory School of Medicine
NHAMCS is endorsed by the following professional organizations:
- Ambulatory Surgery Center Association
- American Academy of Ophthalmology
- American College of Emergency Physicians
- American College of Surgeons
- American College of Osteopathic Emergency Physicians
- American Health Information Management Association
- Emergency Nurses Association
- Federation of American Hospitals
- Society for Academic Emergency Medicine
- Society for Ambulatory Anesthesia