ASC name, address, telephone number, and website are taken from three sources according to the following precedence:

• Information may be collected and updated as the result of direct communications with ASCs, news items, etc. Direct communications has the highest precedence over other sources.
• Information may be collected or updated directly from an ASC's website or from a health system's website.
• Information for ASCs without websites may be taken from their most recent Medicare Provider of Services file or the National Plan and Provider Enumeration System (NPPES) file. Data from these sources are only used when information is not available from a website or through direct communications.

An ASC's County (FIPS code) and Core Based Statistical Area (CBSA) are obtained from the CMS Ambulatory Surgical Center data set. Federal Information Processing Standard (FIPS) codes include a three-digit number that defines a facility’s county. The CBSA is a U.S. geographic area defined by the Office of Management and Budget (OMB) that consists of one or more counties (or equivalents) anchored by an urban center of at least 10,000 people plus adjacent counties that are socioeconomically tied to the urban center. Urban and Rural Classifications are determined according to whether an ASC is in a CBSA. Hospitals within a CBSA are considered to be in an Urban area and all others are deemed to be in a Rural area which encompasses all population, housing, and territory not included within an urban area.

An ASC's address is geocoded in order to provide other useful geographic information. Longitude and Latitude designate a specific global location that is useful in mapping and other applications.

The National Provider Identifier (NPI) is the standard, unique health identifier for health care providers and is assigned by the National Plan and Provider Enumeration System (NPPES). An ASC's NPI is obtained from the CMS Ambulatory Surgical Center data set or the National Plan and Provider Enumeration System (NPPES) file.

The Facility ID (Medicare Identification Number), often referred to as a Provider Transaction Access Number (PTAN) or Medicare "legacy" number, is a generic term for any number other than the NPI that is used to identify a Medicare supplier.

The Enumeration Date is the date an ASC's unique NPI number was assigned. It is obtained from the National Plan and Provider Enumeration System (NPPES) file.

An ASC's operating status is determined from the CMS Ambulatory Surgical Center data set.

An ASC's fiscal year end date is taken from the Provider of Services file.

Healthcare Provider Taxonomy Codes are designed to categorize the type, classification, and/or specialization of health care providers. The Code Set is maintained by the National Uniform Claim Committrimary Taxonomy Designation: An ASC must designate one classification as its main line of service and may designate one or more secondary lines of service. Designations are obtained from the National Plan and Provider Enumeration System (NPPES) file.

An ASC is required to have at least one operating room. The total number of operating rooms is taken from the Provider of Services file.