The National Hospital Ambulatory Medical Care Survey (NHAMCS) provides data from samples of patient records selected from emergency departments (EDs) and outpatient departments (OPDs) of a national sample of hospitals. The resulting national estimates describe the use of hospital ambulatory medical care services in the United States. For the 2003 survey, data were collected from 236 OPDs and 475 EDs. Among the variables included are age, race, and sex of the patient, reason for the visit, physician's diagnoses, cause of injury (EDs only), surgical procedures (OPDs only), medication therapy, and expected source of payment. For 2003, additional updates and revisions have been made to the drug characteristics data. The variables CSTRATM and CPSUM have been added to assist in the computation of variances.

The National Hospital Ambulatory Medical Care Survey (NHAMCS) was inaugurated in 1992 to fill a gap in data about ambulatory medical care in the United States. Although the National Ambulatory Medical Care Survey collects annual data on patient visits to physician offices, it excludes the hospital emergency room and outpatient department visits that make up a large part of the total ambulatory care received each year. The NHAMCS provides data from samples of patient records selected from emergency departments (EDs) and outpatient departments (OPDs) of a national sample of hospitals. The resulting national estimates describe the use of hospital ambulatory medical care services in the United States. For the 1997 survey, data were collected from 236 OPDs and 395 EDs. Among the variables included are age, race, and sex of the patient, reason for the visit, physician's diagnoses, cause of injury (ED only), surgical procedures (OPD only), medication therapy, and expected source of payment.

The National Hospital Ambulatory Medical Care Survey (NHAMCS) was inaugurated in 1992 to fill a gap in data about ambulatory medical care in the United States. Although the National Ambulatory Medical Care Survey (NAMCS) collects annual data on patient visits to physician offices, it excludes the hospital emergency room and outpatient department visits that make up a large part of the total ambulatory care received each year. The NHAMCS provides data from samples of patient records selected from emergency departments (EDs) and outpatient departments (OPDs) of a national sample of hospitals. The resulting national estimates describe the use of hospital ambulatory medical care services in the United States. For the 1995 survey, data were collected from 230 OPDs and 391 EDs. Among the variables included are age, race, and sex of the patient, reason for the visit, physician's diagnoses, cause of injury (ED only), surgical procedures (OPD only), medication therapy, and expected source of payment.