Student performance in classes can be affected by lack of attendance and attention while in class. This paper examines the effect of student participation on performance in two Computer Science classes. Attendance and attentiveness are automatically recorded by the videoconferencing software used for the classes. Student participation is measured by multiplying the scores for attendance and attentiveness. In the one class, we found a positive relationship between participation and scores on the final examination. This class is a concepts type class, focusing on theoretical information presented in lecture format. In the other class, we did not find a relationship. This class is a skills type class, focusing on practical skills and involving more hands-on work. The relationship may have been masked by the associated lab and relatively late dropping of the class by multiple students. We discuss the strengths and limitations of this new measure of student participation. Automatic recording of class participation frees up faculty time, which can be used to increase the quality of instruction. Low participation scores early in the course can help identify students at risk. Finally, we make recommendations to record attentiveness even more accurately.