This study investigates a method for measuring knowledge structure development in novice accountants by extending Bonner and Walker [Bonner, S. and P. Walker. 1994. The effects of instruction and experience on the acquisition of auditing knowledge. The Accounting Review 69: 157–178.], which examined the effects of instruction and experience on the acquisition of declarative and procedural knowledge. We employ Pathfinder network scaling, a recently developed and validated measure of knowledge structure acquisition, to determine whether the combinations of instruction and experience previously found to be effective in promoting declarative and procedural knowledge acquisition result in the development of expert-like knowledge structures. Further, we examine the effectiveness of a simple decision aid in promoting the acquisition of expert-like knowledge structures through experience with the decision aid. Results from two laboratory experiments indicate that Pathfinder-based measures of knowledge structure can effectively capture the effects of training and decision aid use on the development of expertise. The findings suggest that assessments of knowledge structures are valuable tools for measuring the effectiveness of training programs, and such assessments can be applied in decision domains where traditional measures of knowledge acquisition are insufficient or infeasible. Finally, the results indicate that properly designed decision aids can impart expert-like knowledge structures to novice decision makers, and these knowledge structures are the key to expertise.