The HCUP Massachusetts inpatient files were constructed from the Massachusetts confidential Case Mix Database files received from the Massachusetts Department of Public Health.

Massachusetts supplied discharge abstract data for inpatient stays from general acute care hospitals in Massachusetts.

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.

The documentation provided by Massachusetts indicates that inclusion of discharges from special units within the hospital (e.g., psychiatric, rehabilitation, long-term care) varies by hospital.

Because of the timing of HCUP data processing for the 1999 NIS, the Massachusetts source file provided to HCUP was an interim file that included records that had failed edit checks. The percent of failed records is very small, ranging from 0.0% to 1.5% (with a mean of 0.4%) for most hospitals. A handful of hospitals had a large percent of failed records. Failed records have one or more of the following errors:

• Invalid diagnosis code *
• Invalid procedure code *
• Invalid or missing birth weight
• Invalid claim certificate number **
• Invalid or inconsistent UB-92 revenue code
• Invalid medical record or person number
• Invalid type of payer *
• Inconsistent primary and secondary payer
• Invalid physician identifier
• Invalid patient or employer ZIP Code. **

* These errors would have been handled during HCUP data processing.

** These data elements are not included in the HCUP data files.

ERRORS in the 1991 Massachusetts SID. Due to an error in HCUP processing, the following correction should be made to the 1991 Massachusetts SID before use:

Delete all records with HOSPID = 25098 (n=2605).

This facility became an outpatient facility in 1991 and is not reported in the 1991 AHA Annual Survey.