Are you still using clickers in your large class? According to Samson (2010), over 90% of students prefer using LectureTools.
LectureTools is a complete suite of in-class tools, including the ability for students to follow along with presentations on their own computers, take notes next to slides, flag slides as confusing, and ask questions digitally. It also incorporates a student-response system which allows the professor to ask live multiple-choice or short answer questions.
LectureTools has been found to result in an increase in student participation (asking questions), student engagement, and level of learning (Samson, 2010). The University of Ottawa has a license for this software, making it free to use for both professor and student.