Recent advances in technology and rapid changes in the world have placed increasingly stringent demands on the human operator in many military systems. The need for improved and more varied skill levels, coupled with current fiscal constraints, requires that modern military training systems must impart the complicated, higher-order skills required to operate modern combat systems in less time and with a lower dollar investment than in recent history. Therefore, the modern training challenge demands an optimization of training resources-a return on investment that results in an uncompromisingly high level of readiness at the lowest possible cost and in the shortest time. The purpose of the present research was to advance understanding of effective training system design by investigating factors that may affect significantly the success of training in terms of performance improvement in the operational environment. The benefit of such work is that it can lead to generalizable training design guidelines that will increase the probability of effective training with a relatively small investment. In order to accomplish this goal, a comprehensive model of training effectiveness was first developed and used as a basis to specify testable hypotheses. A large-scale data collection effort was then conducted with Navy recruits. Results indicated that several "non-technical" factors had a significant impact on training outcomes in this setting. These factors included: self-confidence, task-related attitudes, expectations for training, training fulfillment, and pre-training motivation. These results are discussed in terms of their implications for improving training system design.