Patient classification systems, Part 2: The third generation.

In Part 1 (July/August 1999), the authors reviewed the evolution of patient classification systems over four generations of progress, discussed issues of system credibility, and presented a third-generation patient classification system (3PCS) to address the shortcomings of current systems. In this article, an actual implementation of a 3PCS is presented by the authors in collaboration with system users. The development, implementation, and evaluation of the 3PCS, as well as the overall advantages, are discussed. Finally, the authors share lessons learned and thoughts for the future.