Teaching and learning activities that occurred in large university classes were studied with attention to the extent students are being involved and whether that involvement makes a difference in their attitudes and performance. At the University of Texas at Austin, 19 large (100 students and larger) classes, representing the college of liberal arts, natural sciences, engineering, and business, were studied. Each class was observed at least once a week for one semester. A trained observer recorded the verbal interactions using the Expanded Cognitive Interaction Analysis System. The observation data were analyzed to determine whether differences occurred in the teaching techniques used in different disciplines or by different instructors. Students also ranked instructors according to their effectiveness. Findings include the following: students rated instructors more highly who tested at higher cognitive levels (e.g., gave essay exams); instructors who relied heavily upon visuals were rated lower than those who used them only at strategic points; all of the instructors lectured an average of 80-95 percent of each class session; and there was more student talk per instructor question in the higher-rated classes. Appendices provide numerous statistical tables and graphs of the results. (SW)