This study was directed toward improving the balance and consistency of student participation by thinning, randomizing, and delaying credit for student participation. Each of three sections of a large college course (n = 55) employed a different contingency for choosing the days in which participation credit was awarded: (1) credit units identified ahead of time, (2) credit units announced at the end of the course, and (3) credit units randomly selected by students at the end of the course. For all contingencies, random selection of 2 out of 4 discussion days in each credit unit occurred at the conclusion of the course. The study compared the effects of the different credit contingencies on the percentage of students participating at selected levels across days and units. Students recorded their individual comments during class discussion. External raters recorded the number of timely and repetitious comments per student, the number of comprehension and factual questions posed by instructors, and the amount of positive and negative feedback provided to each student. Results showed that when students knew which units would provide participation credit (Section A), the percentage of non-participants and dominant participants decreased, while the percentage of credit-level participants increased. These results are consistent with previous research (e.g., Krohn et al, 2010) reporting balanced participation when students know in advance the specific units when credit is available for participation. Conversely, when students did not know until the end of the semester which units would provide credit (Sections B and C), participation patterns remained relatively similar across units. The percentage of participants at different levels in Sections B and C fell between the percentages for credit and non-credit levels in Section A. A 50-item survey also was given at the beginning of the course to assess student beliefs concerning class participation. The total survey scores significantly predicted student placement into low- or high-participation groups throughout the course. Logistic regression analyses showed that the primary factor, Personal History and Preference regarding Class Participation, better predicted membership in the low-participant group in non-credit units and membership in the high-participant group in credit units in Section A.