Will integrating the traditional nursing and physician functions and creating a more advanced role for nurses in clinical decision-making and the delivery of care have a positive impact on the cost and quality of care in teaching hospitals? This study was a randomized controlled trial of the impacts on costs and quality of the Collaborative Care Model implemented at the University Hospitals of Cleveland in July 1989. The Collaborative Care Model comprised three elements: 1) integrated patient assessment by doctors, nurses and nurse practitioners; 2) nursing-initiated patient management expanding the role of the nurse in assessing acute patient problems using explicit protocols; and 3) patient-centered case management, a "second generation" of nursing case management designed for heterogeneous populations. This project evaluated this model of care to determine whether it increases the efficiency of hospitals which could ultimately allow them to expand services to underserved populations.