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Dataset: National Ambulatory Medical Care Survey (NAMCS)

Basic Information
Dataset Full Name National Ambulatory Medical Care Survey
Dataset Acronym NAMCS

The National Center for Health Statistics conducts the National Ambulatory Medical Care Survey (NAMCS) to measure the health care utilization and delivery of ambulatory services across various providers in the U.S. The NAMCS is based on a sample of patient visits to a representative sample of non-federal employed office-based physicians primarily engaged in direct patient care. The physician/office survey collects a wide variety of information at the physician/office level while the patient data includes detailed information regarding reason for visit, vital signs, diagnosis and treatments.

NAMCS does not include visits to hospital emergency departments, outpatient departments, department of veterans affairs, occupational health clinics, and institutional clinics. A separate sample of community health centers (CHCs) was added to the survey in 2006.

Key Terms Ambulatory, CDC, Physician visit, Statistics, Survey, Physician office
Study Design Cross-Sectional
Data Type(s) Survey
Sponsoring Agency/Entity

Centers for Disease Control and Prevention (CDC)

National Center for Health Statistics (NCHS)

Health Conditions/Disability Measures
Health Condition(s)

Alzheimer's/dementia, Anxiety disorders, Arthritis,Blood disorder, Body mass index (BMI)/obesity, Cancer, Cardiovascular conditions, Depression, Diabetes, Heart attack, ICD-9/10 diagnostic codes, Infectious diseases, Kidney/renal condition, Osteoporosis,Pulmonary disorders, Stroke

Disability Measures NA
Measures/Outcomes of Interest
Topics Physician practice characteristics and specialty, Patient characteristics, Reason for visit, Medical providers seen, Time provider spent with patient, Continuity of care, Primary diagnosis at visit, Comorbid conditions, Vital signs, Diagnostic/screening services, Immunizations, Medications, demographic and regional information, non-medication treatments and procedures performed/provided, Stage of cancer, Laboratory test results, Health education ordered or provided at visit
Sample Population Non-federally employed office-based physicians practices and patient visits
Sample Size/Notes 2014: 2,179 physicians submitted at data on at least one sampled patient for a total of 45,710 Patient Record forms (PRFs)
Unit of Observation Patient (Physician-patient interaction or visit)
Continent(s) North America

United States

Geographic Coverage National
Geographic Specificity Region
Data Collection
Data Collection Mode Survey; from 2013 onward, an automated tool collects Patient Record Form (PRF) content (Census Field Representative abstraction or from physician/office staff)
Years Collected 1973-1981, 1985, 1989-present
Data Collection Frequency Annual
Strengths and Limitations
Strengths The data include weights designed to produce national estimates of ambulatory medical care services in the U.S. Detailed information regarding patient reason for visit, diagnosis, vital signs, treatments, and medications. Data can be used to measure health care utilization across various types of providers.

Only includes office visits. Federally employed physicians as well as those practicing in the specialties of anesthesiology, pathology, and radiology are excluded from the sample.

Reporting biases due to non-response and incomplete response (physician response/participation rate in 2014 was 54.8% of those found eligible, but only 36.8% provided data for at least one sampled visit). Approximately 29.7% of race and 25.2% of ethnicity data were missing in 2014.

Data Details
Primary Website https://www.cdc.gov/nchs/ahcd/about_ahcd.htm
Data Access https://www.cdc.gov/nchs/ahcd/datasets_documentation_related.htm
Data Access Requirements

Public Use Dataset

Data use agreement, $ Cost (NAMCS restricted data)

Summary Tables/Reports

NAMCS factsheets:


NAMCS web tables:


Data Components

1973-1991: patient visit data file, and a drug mention data file (in 1991, these two files are linkable)

1992-2011: a single file containing patient visit and drug mention data information

2012 onward: a single file containing patient visit and drug mention data, as well as a separate file of data for CHCs NAMCS restricted data (additional information and variables masked in the publicly available NAMCS public use microdata files)


Selected Papers
Other Papers

NAMCS publication list:



NAMCS documentation: 


Survey Methods and Analytic Guidelines:


NAMCS Micro-data file documentation:


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The Rehabilitation Research Cross-dataset Variable Catalog has been developed through the Center for Large Data Research & Data Sharing in Rehabilitation (CLDR). The Center for Large Data Research and Data Sharing in Rehabilitation involves a consortium of investigators from the University of Texas Medical Branch, Cornell University's Yang Tan Institute (YTI), and the University of Michigan. The CLDR is funded by NIH - National Institute of Child Health and Human Development, through the National Center for Medical Rehabilitation Research, the National Institute for Neurological Disorders and Stroke, and the National Institute of Biomedical Imaging and Bioengineering. (P2CHD065702).

Other CLDR supported resources and collaborative opportunities:

Acknowledgements: This tool was developed through the efforts of William Erickson and Arun Karpur, and web designers Jason Criss and Jeff Trondsen at Cornell University. Many thanks to graduate students Kyoung Jo Oh and Yeong Joon Yoon who developed much of the content used in this tool.

For questions or comments please contact disabilitystatistics@cornell.edu