[Update (June 16): Lead author Zdeslav Hrepic pointed me to a follow-up book chapter [PDF] where he and the study co-authors describe using tablet-PCs to counter the problems uncovered in their study. Thanks, Z.]
I’m sure we’ve all heard it from skeptical instructors: Why should I use peer instruction in my class? In response, we often cite Hake’s 6000-student study or the new UBC study by my colleagues Louis, Ellen and Carl. These are still pretty abstract, though: If you use interactive, learner-centered instruction, you can expect your students to better grasp of the concepts.
“Sure, but why?” the instructors ask. “Why does it work?”
I just read a paper that can help answer that question. I ran across it while following a discussion about the Khan Academy videos and whether or not they are good tools for learning. This paper by Hrepic, Zollman and Rebello (2007) asks students in an introductory physics course and physics experts (with M.Sc’s and Ph.D’s) to watch a 15 minute video of a renowned physics educator presenting a topic in physics.
The researchers do a series of pre- and post-tests and interviews with the students and experts to compare their understanding of the concepts covered (or not) in the video. There were some significant differences. A couple that stick in my head. (1) students recalled learning about concepts that were not presented in the video. (2) Only students who knew the correct answers on the pre-test were able to infer the concepts from the video (that is, the questions were not explicitly answered in the video.) The students who did not know the concept before were unable to make the inferences. Like I said, there are significant differences between what the instructor thinks a lecture covers and what the students think is covered.
The paper nicely gives us some suggestions to counter this problem.
And my thoughts about how to use peer instruction to do that.
Making inferences: Experts make more inferences than students. And only students who already know the concepts can infer them from the lecture. Therefore, instructors need to be cautious about relying on students to fill in the blanks.
Some of the best peer instruction questions are the conceptual questions where the answer is not simple recall. No traxoline here, please. Questions that rely on students making inferences are excellent for promoting discussion because it’s likely students will interpret the question differently, make different assumptions and come to different conclusions. <soapbox> All the more reason that students need to first answer clicker questions on their own so they’re prepared to share their inferences. </soapbox>
Prior knowledge: Students’ prior knowledge influences what they perceive and can “distort” their recollection of what the lecturer says. Therefore, it’s essential that the instructor has some idea of what the students already know (particularly their misconceptions) before presenting new material.
A few, introductory clicker questions will reveal the students’ prior knowledge. Sure, maybe these are simple recall questions that won’t generate a lot of discussion. But the students’ responses will inform the agile instructor who can tailor the instruction.
Continuous feedback about students’ understanding: The trail the instructor blazes through the concepts and the path the students follow often diverge during a lecture. The instructor should be continuously gathering and reacting to feedback from the students about their understanding so the instructor can shepherd the students back on track.
Observant instructors can gather critical feedback from the discussions that occur during peer instruction or the students answers on in-class worksheets like the Lecture-Tutorials popular in introductory “Astro 101” classes and other hybrids of the Washington Tutorials. Rather than waiting weeks until after the midterm or final exam to find out students totally missed Concept X, the instructor can discover it within minutes of introducing the topic. Minutes, not weeks! The agile instructor can immediately revisit the difficult concepts. Immediately, not weeks later or never!
I’m much more confident I can answer the skeptical instructor now. “Why should I use clickers in my classroom?” Because they give the students and you to ability to assess the current level of understanding of the concepts. Current, right now, before it’s too late and the house of cards you’re so carefully building come crashing down.