A subject of continuing interest, in these days of increasing class size at the college level, is whether or not class size affects the performance and interest level of students. The consensus of studies conducted in economics and other fields is that there is little or no relationship between class size and student performance [1]. In studies attempting to measure the effect of class size, however, it is difficult to control for the influence of the professor on the performance of students. For this reason, I have conducted an experiment at Auburn University in which I taught both a bmass class (310 students) and three classes (average class size of 35) and compared the results. Tests and course content were identical in all classes. The experiment was conducted by applying regression analysis to the total of 415 students, using each student's numerical grade in the course as the dependent variable, and a dummy independent variable to account for whether the student was in the mass lecture or a small class. Other independent variables controlled for prior grade point average, type of major, class standing and sex. The results show that after the other factors are controlled for (each was statistically significant except type of major), students in the mass lecture scored less than 2 points (out of a total of 100) lower than students in the small classes. This difference is quite small and does not approach statistical significance. R2 for the test equation is .35. An attempt was also made to test whether or not mass lectures affect student attitudes toward economics. Using Chi-square analysis on 205 students who had previously taken the first principles course and were now taking the second, it was determined that the electing of additional courses in economics is significantly less for students whose first course was in a mass lecture, but that exposure to the mass lecture approach does not affect the tendency of a student to major in economics. In summary, the results suggest the following conclusion: 1. The finding of previous studies, conducted under different test conditions-that student performance is not affected by class size-is supported. 2. While the mass lecture method may dampen the likelihood that a nonmajor will freely elect additional courses in economics, a student's choice of major (which in many respects amounts to a career choice) is influenced by factors other than the type of lecture method encountered in the first course in economics.'