Larger classes are often associated with lower student achievement. The author tested the hypothesis that the introduction of personal response systems significantly improves scores in a 250-seat classroom, through the channels of improved attendance and engagement. She focused on how continuous participation with the technology could change learning results. The author found that overall attendance rose when the response system was introduced. Regression results show student exam performance during the semester with technology was improved significantly by I-Clicker points per session rather than attendance, while the reverse holds true regarding unannounced quizzes. (Contains 6 tables.)