Health United States 2020-2021

Emergency department

The National Hospital Ambulatory Medical Care Survey (NHAMCS) defines an emergency department as a hospital facility that is staffed 24 hours a day, 7 days a week, and provides unscheduled outpatient services to patients whose condition requires immediate care. Emergency services provided under the “hospital as landlord” arrangement, in which the hospital rents space to a physician group, are also eligible to participate in NHAMCS. An emergency department is in scope for the survey if it was staffed 24 hours a day. If an in-scope emergency department had an emergency service area that was open less than 24 hours a day, that area is included under the emergency department. If an emergency department is staffed less than 24 hours a day, that department is considered an outpatient clinic. (Also see Sources and Definitions, Emergency department or emergency room visit.)