What types of hospitals are included in the SID depends on the information provided by the Data Organizations and how the files were handled during HCUP processing. Most state government data organizations provide information on all acute care hospitals in the respective state. Private data organizations are often restricted to member hospitals and may not provide information on all hospitals in their state.

Beginning with the 1994 SID, all hospitals reported by the Data Organizations were retained in the SID files. Discharges from facilities such as psychiatric facilities, alcohol and drug dependency facilities, ambulatory surgery facilities, and State, Federal, and Veterans hospitals will be in the SID, if reported by the data source. Prior to 1994, only discharges from community hospitals were retained in the SID.

Community hospitals, as defined by American Hospital Association (AHA), include "all nonfederal, short.term, general and other specialty hospitals, excluding hospital units of institutions." Included among community hospitals are academic medical centers and specialty hospitals such as obstetrics, gynecology, ear nose throat, short.term rehabilitation, orthopedic, and pediatric hospitals. Non-community hospitals include federal hospitals (Veterans Administration, Department of Defense, and Indian Health Service hospitals), long-term hospitals, psychiatric hospitals, alcohol/chemical dependency treatment facilities and hospitals units within institutions such as prisons.

Some community hospitals may not be included in the SID because their data were not provided by the data source. To identify community hospitals, the SID must be linked to the AHA Annual Survey of Hospitals by the AHA hospital identifier.

The following tables show the number of hospitals by year, starting in 1997. The tables enumerate the number of facilities by community hospitals, hospitals not classified as community, and community hospitals not in the SID. Information from AHA Annual Survey of Hospitals was used to determine if a hospital was a community hospital. Some hospitals could not be categorized as community or non-community hospitals because these hospitals could not be matched with AHA information. This occurs when a hospital closed in a previous year or when the hospital does not report to the AHA. This information is not available for the 1990-1996 SID files. The information for the 2006 SID will be available in early 2008.

• 2005
• 2004
• 2003
• 2002
• 2001
• 2000
• 1999
• 1998
• 1997