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National Hospital Ambulatory Medical Care Survey (NHAMCS)

While many people are familiar with the United States Census, which is taken every 10 years as mandated by the Constitution, there are actually over 100 different surveys conducted by the US Census Bureau each year. In this educational series, SBB Research Group summarizes key information from about these lesser-known—but highly important—surveys.

What is the National Hospital Ambulatory Medical Care Survey (NHAMCS)?

The NHAMCS provides information about the delivery of ambulatory care in hospital emergency rooms and outpatient surgery centers throughout the United States. The survey is conducted by the g and incorporated into the Centers for Disease Control and Prevention’s Ambulatory Health Care Database.

Survey data is collected on the number of visits by demographic characteristics (age, ethnicity, gender) as well as the type of institution and geography. In addition, various other details are recorded, such as the patient’s reason for the visit (specific chronic conditions and traumatic injury statistics), the provider’s diagnosis, and services ordered or provided. Information is also collected about treatment, including medication therapy and vital statistics, payment (public/private insurance, Medicare, etc.), and the type of provider (physician, registered nurse, nurse practitioner, or mental health provider).

Methodology of NHAMCS

Findings for the NHAMCS are based on a sample of visits to community health centers and non-federal office-based physicians engaged in direct patient care. A three-stage sampling method is utilized to select geographically defined hospitals and emergency departments.

How is the Data Used?

Data collected by the NHAMCS provides statistics on visits to both hospital emergency departments and outpatient departments.

This data is analyzed by Congress, governmental agencies, and public health organizations to define healthcare policies. Universities, medical schools, and research organizations study the information for educational and policy decision-making purposes. With this data, policymakers can take action around critical health care issues, such as:

  • The impact of the national opioid crisis and the aging US population

  • Healthcare reform and the growing number of uninsured individuals

  • Trends of hospital inpatient to outpatient surgery

  • The use of innovative diagnostic and medical record technologies


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