DOI: 10.3886/icpsr27461.v2
title: National Survey of Ambulatory Surgery: 1994, 1995, 1996, and 2006
title: Version 2

description: The National Survey of Ambulatory Surgery (NSAS) was first conducted during the years 1994, 1995, and 1996 in response to the dramatic increase in the number of ambulatory surgery centers during the 1980's and early 1990's. The purpose of the first three years of the NSAS was to collect data on ambulatory (outpatient) surgery procedures performed in hospitals and free-standing ambulatory surgery centers in the United States. General demographic data pertaining to age, sex, and race were collected. Additionally, the 1994-1996 NSAS collected data on hospital diagnoses, outpatient procedures, the type of anesthesia used during the aforementioned outpatient procedures, and the payment methods for the procedures. Following a ten year hiatus, the NSAS was once again conducted in 2006. This iteration of the survey expands on the previous years' data collections. Like the 1994-1996 NSAS, the 2006 NSAS collected general demographic information on age and sex along with data on hospital diagnoses, outpatient procedures, and the type of anesthesia used during outpatient procedures. The 2006 NSAS collected additional data on patient symptoms, types of insurance, various time measures related to the medical procedures, and multiple measures pertaining to the status and health of the patients.
description: The 1994-1996 and 2006 NSAS records were weighted to allow inflation to national or regional estimates. The weight applied to each record is called WEIGHT. To produce an estimate of the number of discharges, the weights for the desired records must be summed.
description: The 1994-1996 NSAS used a multistage probability design with some facilities selected with certainty and others sampled with varying selection probabilities. Independent samples of hospitals and free-standing surgery centers were drawn. Noncertainty facilities were selected using a stratified cluster design employing 198 Primary Sampling Units (PSU's) and stratification by facility type, ambulatory surgery status of hospitals, facility specialty, and geographic region.
The 2006 NSAS sampled facilities using a multistage probability design with facilities having varying selection probabilities. Independent samples of hospitals and free-standing ambulatory surgery centers were drawn. The 2006 NSAS did not employ the stratified cluster design used by the 1994-1996 NSAS. Like the 1994-1996 NSAS, the 2006 NSAS stratified facilities according to facility type, ambulatory surgery status of hospitals, facility specialty, and geographic region.
description: Datasets: 
DS0: Study-Level Files
DS1: National Survey of Ambulatory Surgery, 1994
DS2: National Survey of Ambulatory Surgery, 1995
DS3: National Survey of Ambulatory Surgery, 1996
DS4: National Survey of Ambulatory Surgery, 2006
description: The hospital universe includes noninstitutional hospitals exclusive of federal, military, and Department of Veteran's Affairs hospitals, located in the 50 States and the District of Columbia. Additionally, only short-stay hospitals (hospitals with an average length of stay for all patients of less than 30 days) or those whose specialty was general (medical or surgical or children's general) were included in the survey. Lastly, the hospitals must have had six beds or more staffed for patient use.
The free-standing ambulatory surgery center (FSASC) universe includes only those facilities regulated by states or the Health Care Financing Administration (HCFA), for Medicare participation.
description: record abstractsStarting in 2007 the National Survey of Ambulatory Surgery (NSAS) will no longer be conducted as an individual study. Beginning in 2009 the NSAS will henceforth be incorporated into the National Hospital Ambulatory Medical Care Survey (NHAMCS).