Measuring severity: how sick is sick? How well is well?

The need to measure severity of illness of hospitalized patients is becoming more and more apparent. Numerous studies have found that DRGs (and other case-mix systems based only on discharge abstract data) provide a poor explanation of variations in resource use. If inequitable prospective payment results, difficulties in hospital management may be dealt with by strategies based on socially undesirable patient selection. The manual Severity of Illness Index was designed to quantify severity of illness of hospital inpatients, but was subject to a number of criticisms. Therefore, a second-generation system, called the Computerized Severity Index, has been developed that incorporates many state-of-the-art features and meets criticisms of the manual Severity of Illness Index.