This article introduces a simulation, Marketplace Live, and compares students' simulation performance with their course performance. The sample is drawn from 13 sections of the author's Marketing Concepts (Principles of Marketing) course. The results support the idea that marketing simulations do contribute to learning marketing concepts. Evidence for this included (1) the partial mediation of academic ability on overall course performance by effort (indicated by time) and simulation performance, (2) a correlation between improvement in simulation performance with course grade improvement, and (3) correlations between simulation performance measures and performance on the final (comprehensive) course exam.