This study discusses a statistical model to estimate costs associated with drug-related problems in nursing facilities. Using decision analysis techniques and an expert panel of physicians and pharmacists, investigators designed conditional probabilities attributable to drug therapy. Their findings suggest that, for every dollar spent on drug therapy, nearly $1.33 in health care resources are consumed in the treatment of drug-related problems. The authors conclude that improved collaboration among physicians and pharmacists in the nursing home population is likely to reduce the economic impact of drug-related adverse events.