Plan and Operation of the National Hospital Ambulatory Medical Care Survey

In 1991, the National Center for Health Statistics inaugurated the National Hospital Ambulatory Medical Survey (NHAMCS) to gather and disseminate information about the health care provided by hospital emergency and outpatient departments (OPDs).

This report, Plan and Operation of the National Hospital Ambulatory Medical Care Survey, describes the background and development of the NHAMCS and provides the survey design and methodology.

The sampling frame for this survey was compiled from hospitals in the Hospital Market Database. Hospitals with an average length of stay less than 30 days and whose specialty was general children's general were included. The Hospital Market Database contained 6,249 hospitals that met this criteria. Of the eligible hospitals, 89 percent had emergency departments (EDs) and 90 percent had OPDs.

This report describes in detail the data collection procedures, i.e., field training, hospital induction, ED and OPD service area inductions, field quality control, and confidentiality. Also included are the data processing methods, estimation procedures, reliability of estimates, and data dissemination.

This page last reviewed January 11, 2007