Since their adoption, diagnosis related groups (DRGs) have been criticized for relying too much on the principal discharge diagnosis, for not taking the secondary diagnoses into account, and for ignoring the severity of a patient's illness or illnesses. Four case-mix and severity systems, Disease Staging, Patient Management Categories, MedisGroups, and Computerized Severity of Illness, offer alternatives to DRGs by either classifying patients into diagnostic categories or producing overall case severity scores. While most hospitals are likely to continue using DRGs or whatever successor is prescribed by regulation, some may find it useful to look seriously at these alternatives as a means of measuring the consumption of healthcare resources.