Students Talk Back in the Lecture Hall
By Lauren Marsh
He teaches economics in a room that holds up to 110 students, and on any given day, 95 percent of them are in their seats. And when Donald Liu, professor of applied economics, poses a question to the class, he hears from every single student.
His students respond using a Student Response System (SRS), also known as clickers. They are the size of small TV remotes and enable each student to register a response to a multiple choice question posted on a PowerPoint slide. Not only can he see how each individual student has answered, but he is able to immediately aggregate and share the results with his class.
Liu was motivated to adopt the student response system because he couldn’t get his students engaged. He’s a gregarious, friendly man—in fact he prints out the names and faces of his students and memorizes them while sitting at traffic lights! But the large lecture format thwarted his attempts to engage all but the most outgoing or motivated students in conversation. Day after day he would “try to get a reaction” but his students would “just sit there.” He tried the SRS at a colleague’s suggestion. The technology has transformed his classroom. The tool, he explains, makes “everybody equal. No matter what your personality is. No matter if you are shy or not, everybody has an equal voice.”
Of course any technological innovation involves a learning curve. Liu introduced the SRS into a comparatively safe environment: he did a two week trial in a class of 30 students. He found that his students were very enthusiastic about the technology and with their input he established a routine that he has refined over the years. He introduces three topics in a class session and devotes approximately 15 minutes to each. He’ll lecture on a topic for 10 minutes, then post a multiple choice question. Students have 2 minutes to discuss the question or do computation before they use the clickers to “vote” for the correct answer. As a class, they review the question, discuss the answer, and clear up any misconceptions represented by the incorrect answers. Students earn two points for each correct answer, one point for an incorrect answer, and zero points if they don’t respond. The questions therefore add up to 12 percent of a student’s total grade. The extremely high attendance suggests this approach motivates students to attend.
Pop quizzes, after all, are a mainstay of the large lecture classroom as they purport to motivate students to be in class and be prepared. Students typically revile them and no one would argue that they contribute to learning as much as to the administrative challenges of the large classroom. But Liu’s approach is different in some significant ways. He encourages students to collaborate on responses; in fact he assigns seats so that students build working relationships as the semester progresses. As a result, he says, students become part of learning communities that support their work in the class.
As to tips for instructors interested in using a SRS: Liu says the key is carefully crafted questions. A physicist at Harvard, Eric Mazur, coined the term ConcepTest for multiple choice questions that gauge student understanding of a concept, reveal commonly held misperceptions, and are challenging enough to engage them in discussion and problem solving. Liu poses three general kinds of questions: those that test students’ understanding, those that encourage them to apply information they’re learning, and those that address concepts not yet covered in class in so he can gauge prior knowledge and pique students’ interest. Questions have to be hard enough to challenge students but not so difficult as to discourage them. The art of writing effective questions is infinitely perfectible—Liu is in the process of revising his question database.
Professor Liu also has a second tip for instructors who use clickers in a class: bring extra batteries.
