Many surgeries are performed in freestanding, or “same-day,” ambulatory surgery centers (ASCs). The number of freestanding ASCs in California has increased dramatically over the past 11 years. However, due to a legal decision that removed reporting requirements for ASCs in the state, little is known about the volume of procedures, type of procedures, and financial operation of the vast majority of these facilities.

California’s Ambulatory Surgery Centers: A Black Box of Care looks at the most recent data on the supply, use, quality, and finances of freestanding ASCs in California, as well as trends from 2005 to 2016.

Key findings include:

• From 2005 to 2016, the number of Medicare-approved freestanding ASCs increased by 26%, from 626 to 791, while the number of operating rooms (ORs) in these facilities increased even more, from 1,311 to 1,905 (45%). In 2016, California had slightly fewer freestanding ASC ORs per 100,000 population than the average state.
• Despite the decline in the number of facilities and surgeries reported to the Office of Statewide Planning and Development (OSHPD), the number of surgeries per facility remained relatively stable, around 2,500.
• Among freestanding ASCs that reported data to OSHPD, private insurance was the dominant payer, representing 41% of ASC encounters, while Medi-Cal covered one-third.
• In 2017, the Centers for Medicare & Medicaid Services (CMS) started publicly reporting quality measures for ASCs. In the first set of measures reported, California performed similarly to the national average.

The full 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.