Empirical evidence suggests that people perform poorly in dynamic tasks. The thesis of this article is that dynamic decision performance can be improved by helping people to develop more accurate mental models of the task stems through training with debriefing supported computer simulation-based interactive learning environments (CSBILEs). I report a laboratory experiment in which subjects managed a dynamic task by playing the role of fishing fleet managers. One group of participants used a CSBILE with debriefing, whereas another group used the same CSBILE but without debriefing. A comprehensive model consisting of four evaluation criteria is developed and used: task performance, structural knowledge, heuristics, and cognitive effort. It is found that debriefing was effective on all four criteria; debriefing improves task performance, helps the user learn more about the decision domain, develop heuristics, and expend less cognitive effort in dynamic decision making.