A methodological framework is presented for representing tradeoffs among alternative combinations of training and aiding for personnel in complex situations. In general, more highly trained people need less aid, and those with less training need more aid. Balancing training and aiding to accomplish the objectives of the system in a cost effective way is the concern. A wide variety of methods, tools, and models is reviewed. These approaches are evaluated in terms of their advantages and disadvantages when used to analyze training/aiding tradeoffs. The use of the proposed framework and its component methods, tools, and models is illustrated by ;-,n analysis of a realistically complex example involving the design of a head-up display for use by truck drivers in long-haul transport. Results demonstrate that the tradeoff issue can be involved in other than an ad hoc manner. Research needed in predictive models, learning processes, and intelligent systems is reviewed. Four tables and nine figures illustrate the discussion. (SLD)