The use of clickers, especially in large classes, has made participation a reality for a lot more students. It's a safe way to offer an answer and an equally constructive way to find out whether yours is the correct answer. Research on clickers and learning regularly documents their positive effects on exam scores. Now the research enterprise is moving to explore more specific questions, such as whether the clicker influence is more significant for some questions than for others. For example, here's a study that looked at the effects of factual and conceptual clicker questions on exam performance.