Methodology
Design and Data This cross-sectional study used data sets created by the University HealthSystem Consortium (UHC), a subset of the data used for a study reported elsewhere. The clinical data set contained patient diagnosis and procedure codes, actual and expected length of stay (LOS). The operational data set contained direct caregiver hours for each unit. Values for staffing
and outcomes were calculated for each of the 4 calendar quarters for 2005. Data from the UHC did not contain information about nurse education; therefore, a mailed survey to CNOs obtained that information. The final sample included 21 UHC-member teaching hospitals that had contributed data to both clinical and operational data sets and from whom we had complete responses to the education survey. Data for 84 quarterswere available (4 quarters from each of 21 hospitals).The study was approved by the University of California, San Francisco institutional review board.