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2012 September 30

Thoughts about Mazur’s AP50 class

Filed under: Uncategorized — gasstationwithoutpumps @ 12:49
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On Turn to Your Neighbor: The Official Peer Instruction Blog, the latest post is 3 ways to get your students to like doing homework in a flipped class, which talks about Eric Mazur’s Applied Physics class at Harvard.  Eric Mazur is the poster boy for the peer-instruction movement, having gotten enormous improvements in his physics classes on widely accepted tests like the Force Motion Inventory by switching from a lecture-based approach to one using peer instruction.

This post by Julie Schell seems to me a bit misleading, as she provides pictures contrasting an enormous lecture hall with 100s of students with a flipped classroom showing a dozen students in a room equipped for maybe 30 students. Mazur’s poster boy status comes from his getting good results in huge classes, not from small, boutique classes, which many instructors can do well in with many different pedagogical aproaches.  She clarifies in a comment: “34 students, the preceptor is full time, and the room is a large open space with 10 round tables on wheels, each with a large whiteboard, also with wheels.” So the lecture course for 200 and the tiny course for 34 students with a faculty member and a fulltime preceptor are not at all comparable in price per student. Harvard can afford boutique freshman courses, but it is getting very difficult for public universities to do so.

The three ways mentioned in the title are simple:

  1. Graded on effort versus correctness
  2. Autonomy is encouraged
  3. Reflection is built in, rewarded, and the opposite of boring

The first point is questionable.  I think (hope) that what Mazur is doing is grading on the reasonableness of the argument, rather than on getting the same answer as the instructor.  For open-ended physics problems, there can be many different assumptions made, resulting in very different conclusions, all of which are correct in the context of the problem.  That is very different from grading only on effort, as students can put in a lot of effort in doing things in completely wrong-headed ways.  As an engineering professor I put a lot of weight on getting right answers to simple questions, and reasonable answers with good reasoning to complex questions, and I would expect physics professors to have a similar value system.

I think (hope) that Julie Schell has misunderstood what is happening in Mazur’s classrooms, and that what is really happening is that Mazur is assigning complex open-ended problems and assessing the correctness of the reasoning process, and not just effort as Julie claims.  There is a big difference between assigning problems that have many reasonable solutions and not caring whether what the students does is reasonable.  In engineering design classes (like the circuits course I’ve been boring my blog readers about), we often ask open-ended questions where the result is judged by whether the design works, not by whether it is the same as some canonical design.

I like seeing the second point.  One of the biggest problems I have with many approaches to peer instruction, which has so far stopped me from formally using it in any of my classes, is the ease with which students can offload their thinking to their peers. The approach Mazur has of asking students to work on their own first, then mark up their work in a different color during group work may help alleviate some of my concerns about freeloaders. I wonder how well it works with other groups of students, though, particularly those who are taking required classes whose material they are not very interested in.

The third point is again one I have trouble with “They are provided with a reflection handout, on which they write up their own reflections on how they can improve their learning and hand that in with their marked up work.”  I’ve always found such reflection exercises to be rather pointless makework and remain unconvinced that they actually add anything to student learning.  I know that that such reflection is very popular in ed schools these days (often to the exclusion of things I regard as more important), but is there any evidence that it really helps students with anything other than learning how to write bulls**t to satisfy teachers?

A lot of the peer-instruction model seems to rely heavily on students buying into the model and becoming seriously interested in learning the material (as opposed to just passing the class).  Instructors who can inspire their students to care about the material may do equally well with other pedagogical approaches.  (Mazur’s status as poster boy for the movement comes largely from before and after studies with him as instructor, removing a lot of instructor-charisma factor from the studies—the good results he got can be attributed largely to changes in his pedagogy.)

I suspect that peer instruction as described here relies on having enough high-performing students that group discussion corrects misunderstandings, rather than propagating them—or on having a good enough ratio of TAs and instructors to students that group errors can be caught and corrected before they become entrenched.  With the budget cuts over the past 2 decades and the expected budget cuts over the next 2 decades, it is getting harder and harder for public universities to provide an adequate teacher/student ratio.  Although Mazur is convinced that the approach is easily scalable, I suspect that the scaling does not allow the sort of teacher/student ratios that our administration forces on us.

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