The HCUP California inpatient files were constructed from the confidential files received from the Office of Statewide Health Planning and Development (OSHPD).

California supplied discharge abstract data for inpatient stays in general acute care hospitals, acute psychiatric hospitals, chemical dependency recovery hospitals, psychiatric health facilities, and state operated hospitals. California excluded inpatient stays that, after processing by OSHPD, did not contain a complete and "in-range" admission date or discharge date. California also excluded inpatient stays that had an unknown or missing date of birth.

Not all hospitals report a full calendar year of data. Some hospitals close during the year; other hospitals have technical problems that prevent them from reporting a full year.

Included with the general acute care stays are stays in skilled nursing, intermediate care, rehabilitation, alcohol/chemical dependency treatment, and psychiatric units of hospitals in California. How the stays in these different types of units can be identified differs by data year. Prior to 1998, the first digit of the source hospital identifier (DSHOSPID) contains the information. Beginning in 1998, the information is retained in the HCUP variable LEVELCARE. The values for the level of care are defined as follows:

0 = Type of unit unknown (beginning in 1996)

1 = General acute care

2 = Not a valid code

3 = Skilled nursing and intermediate care (long term care)

4 = Psychiatric care

5 = Alcohol/chemical dependency recovery treatment

6 = Acute physical medicine rehabilitation care.

Reliability of this indicator for the level of care depends on how it was assigned.

Prior to 1995. The type of care was assigned by California based on the hospital's licensed units and the proportion of records in a batch of submitted records that fall into each Major Diagnostic Category (MDC). Hospitals were permitted to submit discharge records in one of two ways: submit separate batches of records for each type of care OR bundle records for all types of care into a single submission. How a hospital submitted its records to California determined the accuracy of the type of care indicated in the first digit of DSHOSPID. Consider a hospital which is licensed for more than one type of care:

• If the hospital submitted one batch of records per type of care, then the distribution of each batch of discharges into MDCs would clearly indicate the type of care (acute, psychiatric, etc.). The data source could then accurately assign the first digit of DSHOSPID.
• If the same hospital submitted all of its records in one batch, then the distribution of discharges into MDCs would be a mixture of acute and other types of care. The first digit of DSHOSPID would be set to "general acute care" (value = 1) on all records and would not distinguish the types of care.

Prior to 1995, most hospitals submitted only one batch of records to California which meant that the type of care indicated in the first digit of DSHOSPID did not distinguish among types of care.

Beginning in 1995. Hospitals in California were required to assign type of care codes to individual records for certain discharges. These discharges included:

• general acute care (value = 1),
• skilled nursing and intermediate care (value = 3), and
• rehabilitation care (value = 6).

For discharges from facilities licensed as psychiatric care (value = 4) or alcohol/chemical dependency recovery treatment (value = 5), California continued to assign the type of care code to all discharges from the facility.

A Very Unusual Community Hospital. One hospital, the Veterans Home of California, also known as the Nelson M. Holderman Memorial Hospital in Yountville (prior to 1998, DSHOSPID=n06281297, where n indicates the facility type; beginning in 1998, DSHOSPID=281297), is very unusual. The majority of the beds are in a nursing home type unit. The AHA Annual Survey defines it as a community hospital; it is included in the HCUP California SID.