Conscientiousness is Key: Incentives for Attendance Make Little Difference.
"This study examined differences in class attendance at different levels of conscientiousness and incentives (3.5% vs. 6% of course points). Results of a 2 × 2 (Level of Incentives × Level of Conscientiousness) ANOVA indicated a significant main effect for conscientiousness. Conscientiousness accounted for 14% of the variance in attendance, compared to 1% for incentives. Attendance appears to be influenced more by conscientiousness than by incentives."
Conard, M. A. (2004). Conscientiousness is key: Incentives for attendance make little difference. Teaching of Psychology, 31(4), 269-272.