We need to think like economists

Yesterday, I heard a student bragging about the thousands of hours he spent playing a certain on-line game. That’s right, folks, you read correctly — thousands… 103, if you’re thinkin’ powers of ten. 

My response to this teenage-boy hubris was, well, less-than-enthusiastic.

What could he have been doing instead? Playing the accordion, shoveling snow, loitering in a shopping mall, walking his ferret, sleeping… dare I say “studying”?

This made me think of economics — the “dismal” science.1

Permit me to explain:

I recently had the good fortune to attend the 25th Biennial Conference on Chemical Education at the University of Notre Dame. There were many fine sessions; I absorbed plenty of ideas and approaches. But here’s the kicker: I will use only a few. It’s all about marginal cost and marginal benefit

We need to evaluate everything we use in the classroom. Every idea comes with a cost, the most important of which is usually time. Does the time required to run an activity in class, and for the students to do what they need to do, justify the instructional — or learning — outcome? Does the marginal cost of the activity justify its marginal benefit? In my now lengthy teaching career, I’ve seen more than one flavour-of-the-month idea or directive that does not offer a favourable benefit-to-cost ratio.

A couple of good examples come to mind: 

I begin AP Chemistry with a study of redox and electrochemistry.2 A teacher can find plenty of labs where students kick off the unit by constructing electrochemical cells, measuring voltages and the like. This is a time-consuming activity, with, in my opinion, not a lot in the way of understanding. This topic is so new, that a teacher-demonstration, complete with detailed explanations/videos/PowerPoint slides/handouts has a much bigger pay-off in terms of student understanding. Okay, it may be less “fun” to listen to me — but… 

In grade 11 Chemistry, I — and my students — find the mole concept pretty straight-forward. I see no need for the mole-related hoopla; it’s a time-stealer.3 

We must explain this way of thinking to students. For example, does the marginal (time) cost of “studying with a friend”, justify the marginal (learning) benefit, when a student can simply study alone? 

I would say, however, that the marginal cost of regular —and moderate — exercise is far outweighed by its marginal 4 benefit.

Our students should also be aware of opportunity cost. Time spent goofing off is more than that — it’s time NOT spent studying. Time spent hanging around in your friend’s basement means time NOT spent playing basketball. Virtually everything we do comes with an opportunity cost. 

Economists also tell us that “human beings respond to incentives”. I love this. It means that we’re supposed to act in our best interest; we’re supposed to act in a way that will make us “better off”. I’d like to propose Jansen’s corollary: “Many teenagers will act in their self-interest, as it relates to the next ten minutes, or the next ten marks.”

Tell students that a quiz or lab report is “formative”—they don’t care; they don’t study. “Why should I spend time preparing when it doesn't count, Sir?” This makes sense. I think that everything a student submits should count for marks. It’s incentivization, pure and simple. That said, quizzes need not count for a large percentage of the final grade — not every quiz or set of post-lab questions need to break the grade-bank. 

So there it is, folks: We need to teach chemistry … like economists.

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  1. Dismal science is a term coined by Scottish writer, essayist and historian Thomas Carlyle to describe the discipline of economics. The term dismal science was inspired by T. R. Malthus' gloomy prediction that population would always grow faster than food, dooming mankind to unending poverty and hardship. (see Wikipedia)
  2. Studying oxidation-reduction reactions at the beginning of the course makes many organic chemistry reactions easier to understand — with a lot less memorizing.
  3. This is my opinion; I understand if you disagree.
  4.  “Marginal” in this article is used as an economic term. It is the difference between two things and can be large — as it is here. It does not mean insignificant.