Teaching at least two courses is necessary in my institution. Because of a very busy schedule and lack of time for doing my other academic duties for the next semester, I am thinking about teaching multiple sessions of the same course (in the same day) for the next semester. The course is the freshman calculus if that matters. The good thing is that the course has many TA's and they grade the exams. In each session (in a big amphi) about 300 students are enrolled. I taught this course at least 6 or 7 times in the past (only one session) without problem.

I write this to ask what are the pros and cons of teaching multiple sessions of the same course? I ask this question because I have never taught a same course in multiple sessions. I found this link http://www.chronicle.com/blogs/profhacker/teaching-multiple-sections-of-the-same-course/38472

But I would like to ask your opinion about this. Especially your personal experience would be helpful to me.

Sometimes when I teach two courses with some similarities (e.g. some intersection between their topics), at times I get confused, I think I have covered some topics in one of them, but in fact I have not covered it. Fortunately I ask the students about that. But for an identical course I don't know what arrives.

This is only one aspect of my question. Feel free to give your opinion about other pros and cons.

  • 8
    since I master the content I never bring notes to the class This makes no sense.
    – user1482
    Commented May 22, 2017 at 22:02
  • 4
    @BenCrowell, not bringing notes to class is ambiguous: it might mean just an outline of topics for the day, or it might mean written-out worked examples. I myself only bring notes as "props" for most lectures, or perhaps, indeed, just a single sheet of paper inside a larger folder enumerating the four or five bullet points for the day, whose filling-out is clear to me... Commented May 22, 2017 at 23:20
  • On the issue of being confused as to what has been covered: I set an ironclad day-by-day schedule in advance. After maybe one or two terms of refinement, I can specify what happens in every hour of class all semester long by memory (appropriate chunking helps). If your memory is that good then you should be able remember a one-page schedule. Otherwise just carry the paper and look at it. Schedule uber alles. Commented May 22, 2017 at 23:51
  • @BenCrowell what i said, was related to the content of that paragraph, I explained why I sometimes forget to remember if I have covered some topics or not. If I take the notes usually it is easier to remember. Anyway I remove that sentence to avoid ambiguity.
    – Name
    Commented May 23, 2017 at 4:09
  • 1
    One way to learn fine details of a subject with great thoroughness is to teach it a number of times. Twice in one semester may help you accomplish that sooner. Commented Jun 20, 2017 at 20:41

4 Answers 4


I've done this. The big con is it can be incredibly boring, but maybe that's just me. And agreed, what did I say to the one class and not the other?! The big pro is it can help you refine your materials and teaching methods. I've had two of the exact same classes taught in the exact same way produce very different results.

Write some things down before you start. If nothing else this becomes a checklist to get you through the semester. Goes a long way to keep from getting confused about what you did or didn't cover.

  • 1
    +1 for refining materials. This is one of the most important ways to hone your own teaching. If everything is a singleton, then you have no way to even begin to figure out what effects came from you and what came from the students.
    – Ben I.
    Commented Jun 1, 2017 at 20:46

The main pro is of course that it cuts your lecture preparation time in half. Since for many courses lecture preparation is the most time-consuming aspect, this is a very significant time savings. That you don't know this already makes me suspect that your teaching responsibilities are rather light. At my institution, a full-time instructional faculty would teach four courses per semester (and at some other institutions it would be five). Even a tenure track faculty member at a nationally ranked liberal arts college will often be teaching three courses at once. In these circumstances it is common to speak of "preps" -- i.e., the number of distinct courses you're teaching. So e.g. an institution with a 4-4 teaching load, it might be a policy that an instructor never has more than two preps per semester.

I have taught a lot of freshman calculus myself, and after you get experienced enough the prep time really dwindles. For instance, if you're going to lecture on integration by parts, you decide that you will introduce the formula by anti-differentiating the product rule, then do a few examples showing various standard techniques, then go back and talk about definite integration, then do a few more examples. I could give that lecture right now and it would go fine. It would go better if I thought more carefully, but I think the quality would level off at about 20 minutes of preparation. You've taught the course enough times that you're probably in a similar situation. But even 20 minutes a lecture adds up. Also, since freshman calculus is just about as minimally prep-intensive as it gets, teaching any other course would increase your prep time. And the non-lecture parts are still more efficient if it's two sections of exactly the same course. Presumably you're writing the exams, and I hope you're writing different exams, but writing two different sets of exams for the same course is still a lot easier than writing exams for two different courses.

As the other answer mentions, you do experience a bit of "Wait, did I say that five minutes ago or 75 minutes ago?" when you teach the same thing twice on the same day. It can feel a little weird...but it's not a problem. If discrepancies arise between the two courses, you had better write them down, because they will be very difficult to remember. You'll always be asking students which section they're in. And finally: yes, it will certainly be less interesting than teaching two different courses, but it sounds like you have plenty of other things to occupy your interest.

I want to end with some commentary. A calculus lecture with 300 students sounds rather outmoded to me. With that many students, there cannot be any reasonable expectation that you will stop to field many student questions: if 20% of the students asked a question, those questions and their answers would replace most or all of the lectures. You are also not grading their exams. Probably you're not holding office hours for 600 students in a meaningful way. So what teaching is really being done here? Is the only reason it's called two sections instead of one is because there's no room to seat 600 students? Are the students really getting more out of your lectures then if you just videotaped them and then they just played later to whoever wanted to see them?

I don't think this is a very good pedagogical choice. At my department we recently adopted a small class initative, in which all precalculus and calculus I courses are capped at 19 students. To cover all these courses we had to hire a ridiculous number of new instructional faculty, which frankly I worry could be bad for the long term health of the tenure track faculty. But as a pedagogical choice, it seems to be working very well. A "lecture" for 19 students is different thing entirely than a lecture for 300 students: the instructor really can interact individually with the majority of the students in a given class period. If you are long term member of your department, I respectfully suggest that you reconsider the practice of having such large lectures.

  • 1
    Steven Krantz in How to Teach Mathematics pegs the prep time at "Thirty minutes can be sufficient time for an experienced instructor to prepare a calculus lecture." (Sec 1.2.) Close enough. The one thing here is that my understanding of the evidence is that small class sizes actually doesn't much difference. There are some science courses with hundreds of students per section incorporating active-learning exercises that claim good results. Commented May 22, 2017 at 22:49
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    @Daniel: We are assessing the effect of small classes in our department. So far it looks good, but we'll continue. In terms of evidence: well, I have internet access the same as you, but here is some: classsizematters.org/research-and-links/…. To say though that having 19 students is no better than having 300 seems pretty extreme to me. In my experience, maybe 25% of my students will see me regularly in my office hours: say, once a week or more. How can 125 students per week come to my office hours? Commented May 23, 2017 at 0:58
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    "for many courses lecture preparation is the most time-consuming aspect" I usually find grading to be more time-consuming. But maybe I'm confusing time-consuming with onerous. Commented May 23, 2017 at 1:12
  • 3
    all precalculus and calculus I courses are capped at 19 students -- Are you missing a zero?
    – JeffE
    Commented May 23, 2017 at 2:54
  • @JeffE: Indeed not. Commented May 23, 2017 at 3:03

In my own direct personal experience, and in observation of many colleagues over the years, I see that, although certainly any particular prep time goes down over time, it can also go up either medium-term or longer-term, depending on one's memory. If one has pointlessly good long-term memory, the issue is not remembering what course content is, but, rather, what one has covered "so far" in this episode. Hence the possible need to brief-note-to-self about this. At another extreme, things might have slipped out of one's mind, e.g., through disuse, so that (even if immediately recognizable) one's notes need to include details.

More directly responding to the question: yes, reduced prep time is a plus, if one needed prep time. A down-side is the extra baggage of keeping track of what was said "earlier today" rather than "last year". Deja vu all over again?

I myself would prefer to teach different things, because my own prep times tend to be not-so-bad, and I'd prefer to think about varying things, even if relatively simple, rather than too-repetitive scenarios. I have some troubles about the deja-vu thing even year-to-year and decade-to-decade, which I admit is an unfortunate side-effect of a happily good memory and decades of experience, but/and I do try to make every day a "fresh" teaching situation, which is easier if each day doesn't already contain duplicates.


As other commenters have noted, you must stay organized when you teach multiple sections. For me personally, teaching multiple sections is a joy. However, I want to bring attention to one further advantage and one further disadvantage that I don't believe have been articulated yet:


You get a chance to learn to be a much better teacher. If something you do works in one section, but not the other, then there is reason to believe that your delivery may have been problematic. If it works in neither, then you have very good information that the problem is with you.


Designing multiple exams (assuming that your examinations are in class), or having to worry about students passing information on to students in the next section. One way you can get around this is by designing n+1 exams, where n is the number of sections you have, and using one as a "practice" exam to negate the advantage that the second section will gain by having knowledge of the types of questions you ask and how (generally) difficult the examination is.

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