Time is power. A company that gets products to its customers faster than its competitors strengthens its market position; therefore management students should learn how to reduce lead times. The counterintuitive mathematical principles that drive lead time and the complex system dynamics of operations management make the skills of reducing lead times difficult to teach. Mathematical modeling (queuing-theory or simulation-based) is an effective tool for teaching these skills. In evaluating modeling approaches in the classroom, it is important to consider model quality and student affective outcomes, such as motivation and empowerment. Queuing-theory-based models increase students' abilities to reduce lead times more than simulation-based models. Using a classic teaching case, we compare the two approaches.