In order to optimize the design and operation of modern military aircraft systems, methods are needed to measure the mental workload of the human operator. While numerous candidate metrics are now available for this purpose, little prescriptive information exists to guide their selection and application. This paper describes the development of a standardized methodology for the evaluation of workload measures against several theoretical and practical criteria. The central feature of this methodology is a set of representative loading tasks selected to place demands on primary information processing resources of the operator. Results are reported from an initial evaluation study in which a subset of these standardized tasks were employed to assess the characteristics of a behavioral workload measure.