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Career Advice

Trial and error (and cursing): How to teach large classes


It’s three in morning. I can’t sleep. I’m sweating and anxious. In three hours I have to stand in front of 600 undergraduate students and try my best not to pass out. Like an athlete before the big event, I’m envisioning my lecture slide by slide, which takes my heart rate into overdrive. How did I – an introverted genome geek – find myself in this predicament?

Six months earlier, the chair of my department had cast this course in a different light. “Dave,” he said, “second-year genetics is a piece of cake and perfect for you. It’s part of the biology core curriculum, will look great on your tenure application, and is an excellent opportunity to hone your teaching skills,” – which up until this point had only been tested in the arena of a tiny seminar course. “Sign me up,” I said, and then confidently walked out of the office right before my knees got weak thinking about Natural Science 145, the biggest lecture hall on campus.

I arrive to my lab an hour before my first class and gulp coffee as I go over my slides one final time. (I’ll soon discover that too much coffee and too much practice result in a shaky, stale performance.) I make my way to the main doors of 145 and watch countless bodies funnel into the room.

This bull ring of a lecture hall is more complicated than I anticipated. I fiddle with the intricate lighting system, getting loud applause when the room descends in darkness. I then successfully project my email inbox onto two humongous high-definition screens. “Shit,” I exclaim through the surround sound audio system as I struggle to find the PowerPoint presentation, which I should have left open or at least easily accessible on my MacBook desktop. Once the laughter subsides, I start my lecture.

Perched in front of me on the podium are dozens of smartphones recording my every stutter and bad joke. “Shit,” I say again, but this time no one hears me: the batteries are dead in my microphone. A student in the front row points to a small cardboard box full of batteries and soon I’m back on track, but I finish my talk 15 minutes early. The combination of fear and Tim Hortons has made me the Usain Bolt of biology lecturers.

Before I can take solace in that I’m one lecture closer to the finish, I’m swarmed by a large group of students who bombard me with questions. I direct the swarm outside of the classroom, but still I hold up the next class.

Back in my office, I try to work on a manuscript. It’s no use. Later, I’ll figure out that it’s best to go for a walk or to the gym immediately after a large lecture, rather than try to be productive. But for now I stare blankly at my computer screen contemplating that in less than 24 hours I’ll be delivering the same lecture to another section of six hundred students. To take my mind off this fact, I reply to some emails. My goodness, I have 42 new messages!

Over the coming months, the emails will continue to pour in and I’ll recognize that my inbox is an instrument of torture rather than of communication. I’ll learn that online course management systems are designed to infuriate teachers but are as important and central to the course as the lectures themselves – who would have thought that a frequently asked questions page could be so useful?

The mid-term exam teaches me a whole new set of lessons, not the least of which is how to rotate among nine different rooms in four different buildings at opposite ends of campus. But no matter what the room, within minutes of the exam starting I’m quickly informed of every grammatical and logical error that I managed to introduce into a few dozen multiple-choice questions, each of which took blood, sweat and tears to design. Soon I starting thinking: a) quit my job, b) turn to the bottle, c) move to California, or d) all the above.

By the end of the semester, the students stop laughing at my inexperience and start listening to my lectures, which improve. I’m now an expert at changing batteries, illuminating auditoriums, and herding young adults into hallways. Every final exam question is vetted twice.

In June I received a thick folder of course evaluations. There are hundreds of comments, ranging from cruel to hilarious to constructive. “Dr. Smith lacks the wisdom and experience of older profs.” This is true. But it’s the ones like this: “You’ve made me love genetics, which I never thought could happen,” that keep me going and make it all worthwhile.

David Smith is an assistant professor in the biology department at Western University. He can be found online at

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  1. Terry Bridges / November 7, 2015 at 00:28

    David, thank you for this very honest account of teaching a large-lecture course. The most students I ever taught was 200, but I can remember many of the feelings you had. I was never completely comfortable teaching in that fashion– I often thought it was more performance than teaching. There are certainly things you can do with large classes like this, such as peer instruction and small-group discussions, but it is certainly not an ideal way to teach.

  2. Patrick Howard / August 8, 2017 at 05:23

    I feel for the author. It is impossible to teach 600 students in any way that reflects what it means ‘to teach.’ Lecture, yes, transmit information through slides, yes, but teach? No. Changing batteries, illuminating rooms,and herding students are not teaching skills. Until we stop short changing undergrads with an economy of scale mindset and taking their money (and lots of it) for a substandard educational experience, instructors like Prof. Smith will continue to be asked to do the impossible.