Since 2002 we have been investigating the use of an electronic classroom communication system in large first year lecture classes. Handheld keypads were distributed to teams of students during a lecture class. Students used the keypads to answer two step multiple choice problems after a discussion within their group. The questions were generated using students' answers from previous exams. We have evaluated our use of the classroom communication system using a survey about how comfortable students are with this type of interaction. In addition, we have tried to determine if the use of the classroom communication system can be linked to student performance on exams. Our results show that students are comfortable with this technology and feel that, on the whole, interactive lectures are useful. At a first glance, there is an improvement in students' exam performance, but there are too many competing factors to clearly say that this improvement is solely due to the use of the classroom communication system. Even though this paper is based in physics and a physics example is used to illustrate points, the technique can be applied to other discipline areas.