The APACHE III data base reflects the disease, physiologic status, and outcome data from 17,400 ICU patients at 40 hospitals, 26 of which were randomly selected from representative geographic regions, bed size, and teaching status. This provides a nationally representative standard for measuring several important aspects of ICU performance. Results from the study have now been used to develop an automated information system to provide real time information about expected ICU patient outcome, length of stay, production cost, and ICU performance. The information system provides several new capabilities to ICU clinicians, clinic, and hospital administrators. Among the system's capabilities are: the ability to compare local ICU performance against predetermined criteria; the ability to forecast nursing requirements; and, the ability to make both individual and group patient outcome predictions. The system also provides improved administrative support by tracking ICU charges at the point of origin and reduces staff workload eliminating the requirement for several manually maintained logs and patient lists. APACHE III has the capability to electronically interface with and utilize data already captured in existing hospital information systems, automated laboratory information systems, and patient monitoring systems. APACHE III will also be completely integrated with several CIS vendors' products.