Category: peer instruction

If you want them to think like experts…

I spend a lot of time thinking about how and why peer instruction works and helping instructors improve their technique. The other day, I had an experience that crystallized for me the difference between peer instruction and students merely clicking their clickers.

The instructor I was observing, who gave me permission to tell this story, was teaching a political science class about gender and politics. During the class, she asked a clicker question something like this:

Where does the US rank in the world when it comes to
the percentage of women in elected positions?
A) 12th
B) 34th
C) 78th
D) 112th

Here’s what was supposed to happen…

The students would vote. Then they’d “turn to your neighbors and convince them you’re right.” The students would help each other remember the correct answer, 78th, and then spontaneously launch into a discussion about how that’s surprising because of ABC and interesting because it’s DEF but not GHI and so on, bringing in all the interesting, conceptually challenging ideas that political scientists explore and debate.

That’s not what happened, though. Sure, they voted. The even split across all four answers showed they didn’t know the answer and were guessing. And when she asked them to turn to their neighbors, the room didn’t crescendo with conversation. There was some brief murmuring

“What’d you pick?”
“Huh. I picked 34th.”

And that was it. There was no interest, no conversation, no debate.

The problem, I think, was not with the students but with the question. It didn’t require students to confront their understanding, take a stance and be prepared to defend it. It simply required them to remember some fact from some book somewhere. In other words, just the kind of low-level knowledge we often scoff at when we say, “Oh, this course isn’t about fact and memorization. No, this course is about gathering evidence to form and then defend arguments.” Not to pick on the Humanities, I often hear from STEM instructors, “…No, this course is about problem-solving and applying the theory to real world applications.”

Here’s a better clicker question:

The US ranks 78th in the world when it comes to the percentage of women
in elected positions. In your opinion, why is this surprising?

A) Because it shows ABC
B) Because it’s an example of DEF
C) Because it contradicts GHI
D) Something else

The fact that requires memorization? Just give it to them. Most importantly, seed the conversation with the concepts you want them to grapple with. They’re not expert enough, not yet, to spontaneously come up with ABC, DEF and GHI, so spark the conversation, especially if one of the choices is a common misconception that needs confronting.

With a question like this, and effective peer instruction “choreography”, the students first do a solo vote where they have to decide, each in their own heads, what they believe about the concept. This solo vote is critical because it prepares them to contribute to the discussion with their peers that follows. For 30 seconds or a minute, the room will be filled with political scientists. Or at least, students practicing to become political scientists, getting immediate feedback from their peers and the instructor. That’s what peer instruction is about.

[Update Jul 5, 2013] One of my Summer projects is (finally) reading Ken Bain’s What the Best College Teachers Do. In summarizing how the best college teachers conduct their classes, Bain describes the “natural critical learning environment”

More than anything else, the best teachers try to create a natural critical learning environment: “natural” because students encounter the skills, habits, attitudes, and information they are trying to learn embedded in questions and tasks they find fascinating — authentic tasks that arouse curiosity and become intrinsically interesting; “critical” because students learn to think critically, to reason from evidence, to examine the quality of their reasoning using a variety of intellectual standards, to make improvements while thinking, and to ask probing and insightful questions about the thinking of other people. (p. 99)

Where I see the clearest connection with the questions used in peer instruction is one of the characteristics of a natural critical learning environment”

[T]he natural critical learning environment also encourages students in some higher-order intellectual activity: encouraging them to compare, apply, evaluate, analyze, and synthesize, but never only to listen and remember. Often that means asking students to make and defend judgments and them providing them with some basis for making the decision. (p. 102)

The original peer instruction question, “Where does the US rank in the world…” asks students only to remember. A good peer instruction question (and a well-choreographed episode of peer instruction) forces students climb higher into Blooms’s taxonomy.

Students, teachers, #flipclass and the transitive property

In math, it’s called the transitive property:

If A=B and B=C, then A=C.

And it jumped off my iPhone screen this morning while I was reading my morning stream of tweets on Twitter.

I spend a lot of time thinking about peer instruction with clickers, like this, this and this, which naturally leads to discussions about “flipping the classroom.” That’s when students do work before class, like reading the text in a  guided way or watching videos created of the instructor, where they learn the simple, background material. Then, they come to class prepared to engage in deeper, conceptually challenging analysis and discussion, often driven by peer instruction.

If you look on Twitter for #flipclass (that’s the Twitter hashtag or keyword the community includes in relevant tweets), it’s not long before you find Jen Ebbeler (@jenebbeler). She teaches Classics using a flipped class model. This morning, Jen tweeted

The last part, it’s “not about the videos but what the instructor does in class” evoked another quote familiar to most everyone involved in astronomy education research and teaching the introductory, survey course we call Astro 101. At the heart of the Lecture-Tutorials lies this mantra

It’s not what the teacher does that matters; rather it’s what the students do that matters.

And therefore, by the transitive property, when it comes to flipping the classroom,

it’s not about the videos, it’s what the students do in class that matters.

Which is precisely what Robert Talbert (@RobertTalbert) concluded after he flipped in introduction to proofs class. When you flip your class,

  1. you have time in class to doing other things, like clickers, because you’re not wasting time going over the easy stuff anymore,
  2. the students are prepared to engage in the conceptually challenging, “juicy” stuff you want to uncover together.

It’s what you do with that time that matters.

My math teachers always said learning abstract relationships like the transitive property would come in handy in the future. Yep.

A Tale of Two Comets: Evidence-Based Teaching in Action

Comet McNaught
Comet McNaught wow'd observers in the Southern Hemisphere in 2007. (Image by chrs_snll on flickr CC)

We often hear about “evidence-based teaching and learning.” In fact, it’s a pillar of the approach to course development and transformation that we follow in the Carl Wieman Science Education Initiative.

It’s a daunting phrase, though, “evidence-based teaching and learning.” It sounds like I have to find original research in a peer-reviewed article, read and assimilate the academic prose, and find a way to apply that in my classroom. Does a typical university instructor have the time or motivation? Not likely.

It doesn’t have to be like that, though. There are quicker, easier analyses and subsequent modifications of materials that, in my opinion, qualify as evidence-based teaching. Let me share with you an example from an introductory, general-ed “Astro 101” astronomy course. First, a bit of astronomy.

Comets and their tails

Comets are dusty snowballs of water ice and other material left over from the formation of the Solar System. The comets we celebrate, like Comet Halley, travel along highly-elongated, elliptical orbits that extend from the hot, intense region near the Sun to the cold, outer-regions of the Solar System.

Comet's tail
A comet's tails point away from the Sun. The comet is orbiting clockwise in this diagram so the yellow dust tail trails slightly behind the blue ion tail.

As comets approach the Sun, like Comet Halley does every 76 years, the comet’s nucleus warms up. The ice turns to gas which creates a sometimes-spectacular tail. The tail grows larger and larger, streaming out behind the comet until it rounds the Sun and begins to head back out into the Solar System. That’s when something interesting happens. Well, another interesting thing, that is. You may think the comet’s tail streams out behind like the exhaust trail (the contrail) of an airplane but once the comet rounds the Sun, the tail swings around ahead of the comet. Yes, the nucleus follows the tail. That’s because the tail is blown outward by the solar wind so that the tail of a comet always points away from the Sun. (Well, there are actually 2 tails. The ion tail is strongly influenced by the solar wind – it’s the one blown directly away from the Sun. A dust trail also interacts gravitationally with the Sun, causing it to curl out behind the ion tail.)

Teaching and learning

It’s not what you’d expect, the tail wagging the dog. And that’s make it a great opportunity for peer instruction and follow-up summative assessment.

Last December, the course’s instructor and I sat down to write the final exam. We could have used a multiple-choice question

The ion tail of a comet always…
A) points away from the Sun
B) trails behind the comet
C) D) E) [other distractors]

Or perhaps a more graphical version, like this one from the ClassAction collection of concept questions:

Comet Trajectories concept question from ClassAction
A concept question about the shape of a comet's tail from the ClassAction collection at the University of Nebraska - Lincoln. The correct answer is C, by the way.

Both of these questions are highly-susceptible to success-by-recognition where the student doesn’t really know the answer until s/he recognizes it in the options. “What do comets’ tails do again? Oh right, they point away from the Sun.”

Instead, we decided on a question that better assessed their grasp of how comet tails behave. The cost is, this question is more difficult to mark:


Oh, the question was marked out of 2, 1 pt for each tail pointing away from the Sun. That’s not the kind of assessment I mean, though. I’m talking about the assessment that goes into evidence-based teaching and learning. How did the students respond to this question? What it a good test of their understanding?

I went through the stack of N=63 exams and sorted them into categories. It wasn’t hard to come up with those categories, it was pretty obvious after the first 10 papers.

  • 46 students: tails of equal lengths pointing away from the Sun. Yep, 2 out of 2.
  • 5 students: tails of equal lengths pointing away from the Sun with guidelines. Nice touch, reinforcing why you drew the tails the way you did. 2 out of 2. And some good karma in case you need the benefit of the doubt later on the exam.
  • 3 students: drew ion tail correctly and dust tail mostly correct. Good karma for adding extra detail, though the dust trail is too much traily-behindy. Be careful, kids, when you write more than is asked for – you could lose marks.
  • 1 student: tails with (correctly) unequal lengths pointing away from the Sun. Oh, very good! Maybe 3 out of 2 for this answer!
  • 8 students: various incorrect answers. I like this first one (“Oh, geez, there’s something about pointing and the Sun, isn’t there? Ummm…”)

Evidence-based teaching

It’s clear that the vast majority of students grasp the concept that a comet’s tail points away from the Sun. Terrific!

So why are we wasting this question on such an obvious bit information, then? Let me put that another way:  These students are evidently, and I mean evidently, capable of learning more about comets. We thought this <ghost> “Oooooo, watch oouuttt! Comet tails point awaaaaayyyy from the Suuuun…” </ghost> concept would be difficult enough. Nope, yhey surprised us. So let’s crank it up next year. Let’s explore the difference between the ion and dust tails. And that the length of the tail changes as the comet approaches and recedes from the Sun. Next year, the answer that gets full marks will be the one with

  • 2 tails at each position,
  • the ion tail pointing away from the Sun,
  • the dust tail lagging slightly behind the ion tail,
  • short tails at the far location, large tails at the close location

That’s evidence-based teaching and learning. Find out what they know and then react by building on it and leveraging it to explore the concept deeper (or shallower, depending on the evidence.) It’s not difficult. It doesn’t require poring over Tables of Contents, even in the excellent Astronomy Education Review. All it requires is small amount of data collection, analysis and ability to use the information. Hey, those are all qualities of a good scientist, aren’t they?