Original Articles: PDF OnlyFrank Richard G. PhD; Lave, Judith R. PhDMedical Care: October 1985 - p 1148-1155 Buy Abstract The relative homogeneity of medical, surgical, and psychiatric diagnosisrelated groups (DRGs) are examined. Using data from the State of Maryland and the Health Care Financing Administration we studied the amount of variation in resource utilization within the DRGs. The estimated coefficients of variation of resource utilization for the surgical DRGs were found to be significantly smaller than those estimated for both medical and psychiatric DRGs. The authors were unable to reject the hypothesis that the coefficients of variation for medical and psychiatric DRGs were different. These results suggest that hospitals are at substantial but equal risk under a DRG-based payment system for both medical and psychiatric DRGs. © Lippincott-Raven Publishers.