Why we lecture

Last year, Brad deLong did a most excellent dissection of the lecture, how it came to be, and why universities need to rethink the whole approach to learning concept before they get eaten by technology development providing even cheaper content delivery.

I’ve been meaning to editorialize on this for a while, and then Chad planning for start of classes prodded me into action, doubly so when Chad posted a link to jolly nice resource for active learning in physics at Learnification

Now, others have provided expositions on how to teach wellgreat

So I guess it is up to me to risk the wrath of education research pundits everywhere

So, we, the professors, pretty much all sat through lectures, and yeah, a lot of them kinda sucked, we know.
And, yeah, so there’s a lot of research on all these newfangled scientifically proven better educational techniques.
Yet still we lecture, occasionally with some minor tweaks or half-hearted attempts to incorporate fads like clickers.


There are so many possibilities:

  • We’re all just stupid.
  • We want everyone else to suffer like we did.
  • We’re lazy and just keep doing the same stuff over and over again.
  • It is a cost effective way to deliver formal instruction to ridiculously large introductory classes.
  • Sadism.
  • We are radically contrarian and do the opposite of what earnest education researchers advice just to piss them off…

Hey, wait a minute here: we are so totally not stupid!

Ok, so the lecture thing.
Yeah, it really did start as a way to get books copied, for free, a typical set of term lecture notes is about 2-300 pages, your basic monograph.
My set of lecture notes, that I copied meself, are one of the few things I have always carried with me, moving back and forth between continents:
Intro Mechanics; Probability Theory; Wave Theory; Functional Analysis; the legendary Applications of Classical Physics I, II and III; Order of Magnitude Physics…
My precious.
Even Solid State Physics, which really truly sucked beyond belief.

Ideally, the primary teaching delivery would be a wise person at the end of a log, with patience and no committee assignments; unfortunately wise people are in desperately short supply, so apart from a handful of lucky graduate students, and even fewer random undergraduates, about 99.9% of university students don’t get that.

Doesn’t scale.

The next best thing is the tutorial – a PhD some comfy chairs and 3-5 students for an hour, couple of times a week.
That is some Active Learning.
Though, I have to say, tutorials work really well when done in parallel with lectures.

Labs. Well you gotta have labs (for science, natch).
Good departments fight for lab resources to the bitter end.

“Recitation sections” – grad student TA and 20-30 students, for an hour, to complement lectures.
This, as I noted, is the cheap version of tutorials, and, to be honest, they generally don’t work; sometimes, with the right students and awesome TA they help some students, but lets just say attendance at recitation sections if often poor for good reasons.

So what is left is “the lecture”.
Ok, so there are also books, peers, and online resources.
And, you don’t have to actually lecture in lectures; especially not by reading sections of “the book” in deadly monotone as 19 year olds all around catch up on their sleep.

Yet, we do.
With feeble attempts at intonation, humour and the desperate struggle to draw some sort of proactive response from someone, anyone, in the audience.


The lectures, as a series, ideally, provide a coherent framework to guide the student to study.
Now, the student can, of course, get that by other means. They can self-guide, or follow the book, some book, if they must.
Yes, about 15% of them can, self-guide through the material, at any given time.
Some who can not do that fresh out of high school can some time later, and vica versa.
The “15%”, btw, is based on anecdotal observation of students over the years, from a sample larger than most education research samples (most faculty who have taught for any length of time have experienced a sample size large compared to many educational research samples, and many of us assimilate and analyze that data), and, from the graduation rate of for-profit colleges.

The lectures are there to define the topic, the range of topic and the depth of topic, and to lead the student through the topic one step at a time. In the order carefully chosen by the instructor according to the very finest pedagogical concepts…
(quick: intro astro – do you do planets first or last?)

The classic error many students make, is to assume that a university lecture delivers the full content of the educational material intended to be assimilated.
It does not, generally, and I’d argue that to limit the material to just that covered in lecture is a mistake.
Further, being in the lecture, even paying attention, even taking notes, is not sufficient and is not meant to be sufficient.

The lecture tries to hit several input channels for learning: the student, generally, needs to listen, watch the material presented, read the presented material in many cases, and, concurrently, take notes.
For most lectures, trying to do verbatim transcription is an error, except when it is necessary – you should be able to figure out which is which. The essence of the notes is to make the student assimilate the material and summarise the essential points on the fly.

But you’re not done then: you should read the notes, and not just the night before an exam. Ideally, you should also rewrite the notes, organize them and make them coherent, and at the same time read beyond the material and add your own notes.
Yeah, it takes time, a lot of time.
It also helps you get really good grades in hard classes.

You also need to do homework/writing assignments, read through assigned reading material, and further to that – work the examples, do additional problems from the book, or invent your own, and keep reading beyond the assigned reading, find alternative sources then “the book” or the lecture notes.

Ok, so there is still a need to engage the students, to generate interest, and to make them engage actively with the material.
This can be done during the time assigned to lecture, through feedback gimmickry, or through peer instruction (though scaling is a problem there).
One problem there is that this takes time from presenting the material.

Sometimes it is appropriate to reduce the scope of the lectures and focus on themes or concepts, particularly for gen ed classes: but, you can’t really cut mechanics in lectures to engineers, and for majors the cutback in topic coverage causes serious problems later on. We won’t even touch the whole pre-med thing.
We could go to 5 year BSc, in some ways we’re already there, much as the UK went from 3 year to 4 year degrees. But that has issues all of its own.

The real fault there is the failure of K-12 education to provide coherent multi-year education in the sciences, and the overload of gen ed material that really ought to have been done at the K-12 level, but that is beyond the scope of the issue of lecturing.

< curmudgeon-mode-on >
I was going through some active learning guide material and it showed a picture of happy engaged students discussing lecture material in class, as an example of effective learning.

Damn right it is.
Talking the material over with your peers and shaking out misconceptions and then going back and asking the instructor about the issue is very effective learning.


Students ought to be talking to each other about what was in the lecture all the time: walking after class, over coffee, on the library steps, over lunch, drinking beer and during the all valuable late night sessions back in the dorms!

< curmudgeon-mode-off >

I mean that.
Dammitt, that is how professors learn -we sit through each others lectures (but we call them seminars or colloquia to make us feel more important), we are mostly unashamed enough to interrupt to ask questions, and then we arrange for discussion periods, over coffee if we can.

This is how we structure our own continuing education: intense lectures, questions on the fly, and with separate periods for peer discussion and rehashing the material.

Nothing pleases a workshop organizer more than watching the crowd chatter during breaks, even if that makes the next session start late.

Yes, talking to peers works well overall, but it cannot be limited to a couple of minutes a couple of times during class. It ought not to be needed during class.

Turn off the TV, kick the xbox under the couch, mute the cellphone and just talk to the other students all on your own, you don’t need me to tell you when to chat.
You might even like it. Or them.

Oh, and the wise person on a log thing…
Come to office hours.
You are paying for them.

It trashes my precious reading time, but I checked, I compared performance of students who came to office hours before and after: one office hour visit, on average improves grades on tests by 15%.
(caveat: for a sample of student taking large intro gen ed classes who were motivated enough to show up without prompting, your grade improvement may vary).


  1. #1 Brandi Swiecki
    August 12, 2011

    Kudos for this article. I greatly appreciated well-defined/well thought out lectures when I was in college. There is something magical about listening to a professesor describe ideas, at length. Nothing can replace the stimulating experience of the centuries-old tradition of lecture.

  2. #2 Scott H.
    August 12, 2011

    The classic error many students make, is to assume that a university lecture delivers the full content of the educational material intended to be assimilated.

    WORD!!! (Emphasis added.) The trend toward “active learning” I’ve seen at my Institute seems driven at least in part by the fact that far too few students realize that the lecture is just one piece of the learning smorgasbord. It’s an important piece, and in the right hands, a damn effective piece. But just a piece. They have to do the other things you mention to get the full benefit.

    (The other two things that seem to be driving the active learning trend are cost effectiveness, and a tendency of active learning techniques to make classes more uniform. A lecture in great hands is amazing; a lecture in bad hands is apocalyptically dreadful. Our active learning classes are all more or less OK, with far less variation. On the whole, it’s great to cut out the dreadful end of the curve, but it’s sad to lose the amazing end.)

  3. #3 In Hell's Kitchen (NYC)
    August 13, 2011

    A significant percentage of university/college faculty have yet to realize that the percentage of students who are in their classes because they really (really!) want to be there is much (much!) lower than what they think it is.

  4. #4 Quinn O'Neill
    August 13, 2011

    Studies have consistently shown that students learn less from traditional lecture-style teaching compared to alternatives, like group discussions and problem-based learning. The learning that results from lectures also tends to be more superficial – students remember what the prof says so they can spew it on an exam but may not understand the concepts well. Lectures, as a teaching method, are simply inferior to most alternatives that have been studied.

    That said, maybe with the right group of students – those who go beyond the assigned reading, discuss course material with classmates outside of class, and spend time working through examples on their own – lectures might be sufficient. But then they might also be unnecessary. If you’re motivated enough to read the textbook on your own, practice problems, consult friends, and contact the prof outside of class, do you really need lectures?

    People don’t go to university these days because they’re exceptionally motivated and they want to learn, they go because that’s what most people do and because they want a diploma and later a job. I’d wager that your average college student is more interested in partying than in learning, and only interested in learning what they have to in order to get good grades. If profs were to choose their teaching methods so as to maximize the learning of the majority of their students, they’d avoid lectures. But then your average prof these days is probably more interested in his own research endeavors and obtaining tenure than in effective pedagogy. The heart of the problem, in my opinion, is this: formal education is no longer primarily about learning.

  5. #5 Steinn Sigurdsson
    August 13, 2011

    @Quinn – I agree that there are several pedagogical techniques superior to lectures, they are all require more resources. Lectures are cheap. The PER stuff right now, is scrambling to look for cheap pedagogical techniques that improve learning, not techniques that improve learning. Stuff that mimics tutorials without the labour cost of real tutorials.

    You’ll note that (for science) I emphasised the need for labs and homework.
    I also noted that, in my estimation, about 15% of students don’t need lectures because they are motivated enough to self-guide.

    Some students indeed are not at uni to learn; the fraction depends heavily on which university, that is ok, they can play their games and try to get through without learning.

    Improving teaching is really aimed at the middle students, who’d like to learn but don’t know how, those are maybe 30-60% of students, depending again on the university.

    At the Research Universities, research is indeed a major interest of many faculty members. There are many universities with many students where little or no research is done. Most of those lecture. Look at the graduation rates of those who do not.

    @In – most all university faculty used to be students.
    We know.
    Ok, there is a confirmation bias, but most of us also had friends at uni who did not become faculty.
    We know.

  6. #6 Quinn O'Neill
    August 13, 2011

    I agree that there are several pedagogical techniques superior to lectures, they are all require more resources.”

    This simply isn’t true. Take paired or small group problem-solving activities, for example. The prof might present a case or problem, have students spend a few minutes discussing it with others and then open the discussion to the larger group. Only the format of the session would need to change, not the number of instructors or resources. This paper discusses a variety of tried-and-true approaches for incorporating active learning in a lecture classroom. Some of these ideas would be easier with a few TAs but others require little more than an instructor who’s willing to try something different.

    Improving teaching is really aimed at the middle students, who’d like to learn but don’t know how, those are maybe 30-60% of students, depending again on the university.

    If 30-60% of students are at university to learn how to learn, they’re at the wrong place. I’ve taken lots of university level courses, but I’ve not taken one that made any attempt to teach me how to learn. Universities don’t let you in unless you’ve demonstrated some knowledge of how to learn – or at least how to memorize and regurgitate information for academic reward. As most universities rely heavily on teaching methods that have been shown experimentally to be relatively ineffective (lecturing), it would seem that they aren’t a good place to learn how to teach either, unless you stay within the confines of the faculty of education.

    At the Research Universities, research is indeed a major interest of many faculty members. There are many universities with many students where little or no research is done. Most of those lecture. Look at the graduation rates of those who do not.

    I’m not sure what you’re saying here. Are you suggesting that there’s a positive correlation between lecturing and graduation rates among non-research universities?

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