2013 Edition — California’s Ambulatory Surgery Centers

Big business, little data

Laurence Baker, Health Economist and Chair, Dept. of Health Research and Policy, Stanford University School of Medicine


As medical care continues to shift from inpatient to outpatient settings, many Californians are using freestanding ambulatory or “same-day” surgery centers for a wide variety of procedures such as colonoscopies, arthroscopies, eye procedures, and more. There are at least 1,603 operating rooms in 754 freestanding surgery centers in the state, according to the latest data available.

However, little else is known about the freestanding ambulatory surgery centers (ASCs) operating in California. Most of these facilities are for-profit entities, with a significant number owned by physicians. The Medical Board of California, which oversees physician-owned facilities, does not collect data for public reporting.

This report looks at the most recent data on the supply, utilization, accreditation, and finances of freestanding ASCs in California, as well as trends from 2003 to 2010.

Among the key findings:

  • The number of surgeries reported to state regulators dropped from 1,167,583 in 2007 to 120,155 in 2010 after a court ruled that physician-owned ASCs would no longer be licensed by the California Department of Public Health or required to report data to the Office of Statewide Health Planning and Development (OSHPD). Oversight of these ASCs was shifted to the state medical board, which does not track the number of surgeries performed in doctor-owned ASCs.
  • In 2010, the federal government, which does not require detailed reporting from ASCs, indicated there were 754 ASCs operating in California. However, only 56 reported data to OSHPD, down from 495 in 2007.
  • Nearly 98% of California ASCs are investor-owned. Among reporting facilities, operating margins were healthy in every year from 2003 to 2010.
  • Private insurers pay for almost half of encounters at ASCs, and Medicare covers close to one-third.

The complete report, and all the charts found in the report, are available for download below. These materials are part of CHCF’s California Health Care Almanac, an online clearinghouse for key data and analyses describing the state’s health care landscape. See our entire collection of current and past editions of California’s Ambulatory Surgery Centers.