As weapon system complexity grows, operator and maintenance personnel training also becomes increasingly complex. Training equipment, such as simulators, can be more complex and costly than the hardware they support. Program schedules often reflect the development of training materials and equipment before the prime equipment design is stable. This premature development often results in inaccuracies in technical manual content and costly redesign of the training equipment. Adequate planning that takes into consideration technical risk (design volatility) and examines interim measures during the design volatile stage will result in overall training effectiveness and efficiency.