(We can take bets on how many “Why I use <insert tech/gadget here>” posts I will end up having.)
I have, perhaps insanely, jumped right into teaching Intro Bio at the University of Michigan. Here, there are two Intro Bio courses, which can be taken in either order. There is Bio 171, which covers Ecology & Evolutionary Biology (that would be the one I teach), and there is Bio 172, which covers Molecular, Cell, & Developmental Biology (fortunately for everyone, I do not teach this one). There are ~680 students in Bio 171, split between two lectures. The noon lecture is taught by my colleague Barry OConnor, who has quite a bit of experience teaching intro here. I teach the 3PM lecture, and, not surprisingly given that I just got here, this is my first time teaching it. Barry and I each teach the full semester of the course, which will become relevant in a bit.
While I am certainly not an expert in pedagogy, I know enough to know that a problem with large lecture courses is that students can end up not feeling engaged, and that attending lecture can be a passive experience. This lack of engagement can lead to attrition of science majors. How to overcome these challenges is important, because, while there is increased interest in effective teaching strategies and retention of students in the sciences, large lecture courses are not going away. A recent survey, the results of which were reported in the Chronicle of Higher Education, found that 63% of faculty in STEM disciplines (that is, science, technology, engineering, and math) reported “extensive lecturing” in their classes.
What to do about this problem? One fairly easy solution is to engage students regularly in class, and to create opportunities for peer discussion. A very common way to do this is to use clickers, which are sold by a variety of companies (such as this one and this one). My impression is that many (most?) universities have some sort of clicker system set up, but I don’t actually have any data on that and may well be wrong. The clicker technology, of course, is not necessary for classroom discussions – good, engaging teachers have been using peer discussion in their classrooms for much longer than clickers have existed. But, in my opinion, clickers make it easier to get student feedback, reduce the potential for student embarrassment about getting an answer wrong, and allow for anonymous polling (if desired) with instant results that the class can see. Students love seeing the histogram of results appear. (There are good reasons to not have the histogram appear for the class, but I generally show it to them right away.)
Here, I will lay out some of the reasons why I find clickers useful, and give some feedback that I recently got from my students that indicates that they also find them useful. In a future post, I will cover things like how to get started using clickers, different strategies for using clickers (e.g., think-pair-share), and whether to link a student’s grade with the clicker questions.
So, some of the reasons why I find clickers useful:
1. Getting instant feedback. There are times when I think I’ve covered something a lot, but it’s something that is important and I want to make sure the students get it before I move on. For example, in Intro Bio, one thing we really try to teach students is how science is done, so we spend a lot of time going through experiments that were done to test different hypotheses. In the competition unit, for example, we talk about Connell’s classic barnacle experiment. (My guess is that this example is used in every competition lecture given, but maybe I’m wrong.) During this class, I laid out the system and described Connell’s experiment. I then asked them which was the control: the rocks that had both species left on them, or the rocks that had just one species on them. This ended up being a very hard question for the students. Only ~30% of them could correctly identify the control. So, instead of moving on, I then went back through the experiment design to explain why the side with both species on it would count as a control. Understanding controls is obviously really important, and I was happy to spend extra time on it making sure they understood what was going on. Other times, I am happy to see that 80+% of the class understands the concept I’ve been trying to get across, and then I can feel more confident moving on.
2. Generating discussion. Probably the most successful clicker question I’ve used so far this semester was during the meiosis lecture. I put up a picture of a cell and asked the students to identify what 2n equaled. About 2/3 of the class got this correct (2n = 6), with most of the others saying 2n=12. The reason this question was so successful is that one of the students who didn’t get it correct raised his hand to say he was confused. That was fantastic, because it set off a discussion that revealed that much more than 1/3 of the class was actually confused about some key underlying concepts (especially 1. that, even if there are sister chromatids, it still counts as one chromosome, and 2. that the replication that occurs prior to meiosis does not generate the homologous chromosomes, but, rather, the sister chromatids). Those are really, really important points, and the level of confusion and where the problems were only came out because of the opportunity for discussion that started with the clicker question (and with a student who was confident enough to say he didn’t understand).
3. Making students realize that they don’t understand something. When teaching General Ecology at Georgia Tech, a common problem I had was that students thought they understood competition, but, in reality, didn’t. Lotka-Volterra competition models were especially hard, but I felt like I had a hard time convincing students that they should pay attention, because they didn’t know this material as well as they thought they did. Enter clickers. I ended up asking a clicker question where I asked them which direction the zero net growth isoclines should point in. None of the students got it correct. That was eye-opening to them, and I think encouraged them to pay more attention.
4. Breaking up the lecture. This is perhaps the most obvious, but it’s boring to listen to one person talk for 50 minutes straight. Clicker questions break things up a little, get the students chatting with one another, and get them out of passive listening mode, all of which are good things. And, importantly, as is summarized by Roedinger et al., testing makes students retrieve information, and the process of retrieval improves their memory. I’ve shifted over the course of the semester towards having more review questions that force students to recall information from previous lectures. For example, during a lecture on mutations, I asked them a clicker question about different evolutionary forces (including mutations), which was something we had covered in class earlier in the week.
5. Scaffolding. In some cases, I knew that, if I asked students to go from concept A to concept E in one leap, they would have a hard time with that. But, if I had them work their way from A to B to C to D to E, they would probably get there. For example, when teaching (in General Ecology) about life history theory, I’ve had them walk through the different steps that would lead to certain predicted life history trade-offs, using a series of clicker questions. I haven’t been doing this last one as much this semester, in part because the other section does not use clickers. Because of that, we made a decision at the beginning of the semester that any essential information would be given on the slides I give to students, to try to keep things even between the two sections. That makes it harder to have them work things out for themselves. When teaching a course on my own, I leave blanks in the notes I give the students. They then have to fill those in in class, sometimes based on what they had worked out for themselves over the course of the lecture. I prefer that approach, but it hasn’t been possible given the structure of my current course.
So, I think clickers end up being useful for a bunch of different reasons. I’m sure I’m missing some other benefits – please bring those up in the comments!
Do the students find it useful? Encouragingly, yes! With assistance from the University of Michgian’s Center for Research on Learning and Teaching, we did an anonymous mid-semester evaluation of my students. 78% of students agreed or strongly agreed with the statement “Clicker questions contribute to my learning,” and 81% of students agreed or strongly agreed with the statement “Clicker questions help me process what I just learned.” Those numbers are quite encouraging!
So, overall, I’m a fan of using clickers in large lecture courses, and it seems like students are, too. As promised, in a future post, I will talk more about how to start using clickers, different strategies for using clickers, and questions related to whether and how to incorporate clicker questions into the grading scheme for the course. So, stay tuned! And, if there are other things related to clickers that you’d like covered, please let me know!