The Nebraska Hospital Association (NHA) provides ambulatory surgery (AS) and emergency department (ED) records to HCUP in one single file. NHA collects any type of outpatient record submitted by member acute-care hospitals operating in the state. Information on the record (i.e., revenue codes and CPT codes) is used to identify resources: ED, AS, and observation stay. Revenue codes 450-459 identify ED visits, while the presence of a surgical procedure indicates an AS record. One record can include multiple types of services. Data from freestanding ambulatory surgery centers are not included.

For data year 2001, NHA informed HCUP that the Nebraska outpatient source data files were approximately 80% complete and that the missing claims might reflect patients who lack health insurance and/or less expensive care. Missing claims are primarily hard copy claims that were not submitted by their providers. Hard copy claims are more likely to be associated with private pay and/or smaller third party Commercial payers that do not accept electronic claims. These patients might be more likely to lack health insurance (for whatever reason) and/or to be financially independent. Providers might file some claims on paper if the return on investment for filing them electronically is less obvious. Thus, paper-based claims could conceivably reflect less expensive care.

The Nebraska Hospital Association prohibits the release of discharge records for patients with HIV diagnoses. These discharges were not included in the source file provided to HCUP and are therefore not included in the HCUP files.

During HCUP processing, records with a discharge disposition of "still a patient" were excluded from the HCUP Nebraska ambulatory surgery data.

Using the standard HCUP criteria for assigning records to the 2003 SASD and the SEDD, the source records are separated as follows:

• 38% of source records are assigned to the SASD
• 61% of source records are included in the SEDD
• 1% of source records are excluded.

Please note that for Nebraska, the two CPT codes in the HCUP Core file were used to apply the selection criteria. The CPT codes in the line item detail were not considered. All revenue codes were used for the criteria.

Identifying Freestanding Facilities. The data element FREESTANDING identifies hospital-based and freestanding ambulatory surgery facilities.