Much of the economic education literature suggests that the principles of economics class size does not significantly affect student performance. However, study methods have varied in terms of the aggregation level (student or class), the measure of performance (TUCE or course letter grade), and the class size measure (e.g., students who completed both the TUCE pretest and posttest). The authors perform an experiment with principles students using total exam points as the dependent variable in a model to explain student performance, By using the same instructor for all sections, the authors control variation in instruction, lecture material, and topic coverage; they also account for variation in student abilities. In contrast to many other studies, the authors find statistically significant evidence that small class size has a positive impact on student performance.