The use of Resource Intensity Weights (RIWs*) for equity funding and utilization management assumes validity of the cost estimates, reliability of the patient categorization scheme, equivalence of the bases for cost comparison, and equity of the subsequent resource distribution. This paper examines these assumptions, and concludes that caution must be taken when using the current RIWs and Case Mix Groups (CMGs*) for resource allocation and performance evaluation purposes. RIW has represented a milestone in the history of Canadian health care product costing and management. It would be prudent for health care professionals at the operational level to provide structured and continuing feedback that can contribute to the validation and refinement of these valuable management tools.