Big courses at universities can easily reach several hundred, if not several thousand, students in the lecture hall, just for one course. In these settings, it is almost impossible to generate a highly interactive structure, or there is the genuine risk of chaos involving a discussion of far too many simultaneous voices. Therefore, the main option is to just deliver a lecture, which tries to explain the main issues in pure presentation/monologue format. In fact, this format is not as bad as it may look, after all it has frequently worked a lot better in history at universities than it is given credit for. However, one key issue is timing.
If the lecture is too short, then one does not use the alloted time to really explain the material. If the lecture is too long, the average student’s attention tends to drop dramatically. It is an obvious practical science question any teacher/lecturer/professor has to answer: How is it possible to prepare a lecture, which exactly fits within the allocated time slot?
Of course, there is no perfect method to get the lecture duration correct but here are a few tricks, which I found helpful, just regarding timing:
1) Adapt to the format: It makes a massive difference, which media you use to present the lecture. Electronic presentations via slides, writing on a presentation computer/tablet, using the blackboard, using an electronic whiteboard, or many other options are available. Each tool has its advantages and disadvantages. In terms of timing, it is evident that slides tend to be faster than trying to write out an entire slide. However, using any hand-written strategy could be more flexible to explain details spontaneously. Each format requires different preparations to get the timing right.
2) Develop standard units: Let us suppose you use a computer and slides as your format. Then it helps to measure, how long you are taking for a certain number of slides. Then taking an average yields an excellent basic calculation unit to generate the correct number of total slides. For example, I know that it roughly takes me about 2 minutes per slide at a conference presentation, around 3 minutes in an advanced course and between 4-5 minutes per slide in a basic course.
3) Use a measurement standard: For a blackboard or hand-written presentation, it is a lot harder to measure the standard unit. For example, just using a different size paper, different electronic device for large lectures, or a different pen/chalk can make incredible differences. Hence, it makes sense to make your preparation setup as similar as possible for every lecture preparation. For example, I usually use a standard A4 paper, with given rectangles/lines of a certain size, a left-side margin, and I always use a certain type of pencil. In this setting, every page roughly counts for 20 minutes. Here is an example of this paper format:
4) Just finish on time: As many other lecturers, I have the tendency to go over time to finish explaining a result. A tiny bit of over-time is OK but over-doing it too frequently, is (a) not technically correct, (b) doesn’t really help the students to understand more since they are tired, and (c) tends you to rush things too often. A simple solution is to just stop, finish on time, and force yourself to plan better next time.
5) Visit other lectures: If you are uncomfortable with the planning or actual delivery of your lectures with respect to timing, it is very easy to learn other strategies. In fact, it is not even necessary to go to en entire lecture to learn about other strategies, just the last ten minutes are enough 🙂
There are certainly many other tips and tricks to use. The general message in my personal viewpoint is that just sticking to a standards, has helped me immensely to keep the lecture duration a lot closer to the target.
Last but not least, here is a little poll for all lectures. Suppose you present in a classroom setting of an undergraduate course and use slides (say a standard pdf file without a lot of media elements). How long does it take you to present a slide on average: