Providing an active learning environment and engaging students in classroom discussion could be quite challenging. This study used a quasi-experimental method to manipulate students' incentives for participation in group discussion to investigate its impact on students' learning outcomes. Two research methods courses taught over four years by the author were examined. Eighty samples of students' online discussions were recorded, transcribed, and analyzed to assess the impact of four different strategies on quantity, quality, and outcome of students' group discussions. The results showed significant differences in all aspects. The implications of the results for teachers who plan to use group discussion in their courses are discussed and suggestions for future research are offered.