Severity of illness measurement has recently dominated many regional health policy debates, and some states now require severity ratings for inpatients. We summarize results of a telephone survey of regional activities involving severity data. Parties use severity information either to evaluate hospital resource use or to assist in comparing quality of hospital care. For quality assessment, various constituencies frequently specify different goals for the severity information. Business representatives commonly believe that it can quantify hospital performance and help them target cost-effective providers; in contrast, providers view severity information only as a screen for substandard care, suggesting areas requiring detailed examination.