College instructors often provide homework so that their students can review class material; however some students do not take advantage of these review opportunities. This study compared the effects of a certain reward and a lottery reward on the quiz submission rates and accuracy of 112 college students. In Baseline, quizzes were for practice only and had no programmed contingency; in the Certain condition, two extra credit points were available for submission of a perfect quiz; and in the Lottery condition, students who submitted a perfect quiz were entered into a lottery with one winner (actual probability varied) for two points of extra credit. Submission rates averaged 36.50% for Baseline, 62.00% for Certain and 51.67% for Lottery. A one-way repeated measures ANOVA, followed by Fisher's LSD, found the differences in submission rates between all conditions to be significant at the 0.0001 level. Accuracy rates averaged 82.82% for Baseline, 93.80% for Certain and 93.99% for Lottery. A one-way repeated measures ANOVA, followed by Fisher's LSD found the mean score for the Baseline condition to be significantly lower than the mean scores for the Certain and Lottery conditions (p less than 0.01), but did not find a significant difference between the latter two conditions (p less than 0.05). This study demonstrates that when all other factors (e.g. magnitude) are equal, certain rewards are more effective than lottery rewards at increasing quiz submissions. It is possible that the lottery was less effective than the certain reward, due to the uncertainty (indirect contingency) inherent in the Lottery condition. These results have implications for business settings that use lottery rewards in an attempt to motivate a large number of employees at low costs. Future research should examine the roles of magnitude, probability and contingency in predicting the relative effectiveness of a lottery reward. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]