A Few Rules for Giving a Lecture

I’ve discussed some of the rules for graphics in publications and preparing posters before but I feel it’s time for a more general discussion of lecturing for scientists. All of us have suffered through at least one poor lecture at scientific meetings and some of us many more. If you are a scientist or educator and must give a short talk or a long lecture, you should not panic since there are just a few rules that can help in communication and reduce potential suffering for you and the audience.

First, let the audience know what precisely you will be discussing in your talk – what is the problem and what you are going to present about it. The opening 2 minutes of your talk is when you can lose two-thirds of your audience. If you are a politician, this may be what you wish to happen, but if you are a scientist do not go there. You do not need to begin by stating the obvious – we all know that the earth is round and biodiversity is under threat – but dive into the details of the particular problem you are going to resolve.

Second, if you are showing powerpoints, follow a few simple rules or again you will lose your audience. Do not put more than a few dot points on a slide, or more than 1 or at most 2 graphs or maps. You must not spend more than 1-2 minutes on each slide or those of us with a sleep deficit will have a power nap instead of listening. Use writing in large letters only so they can be read from the back of the room.

Thirdly, do not use acronyms anywhere. Most of us do not know that DAE means ‘demographic Allee effect’ or that RR means ‘log response ratio’ so if your slides contain GDD or DOC or HBL or ODE you may be losing your audience. In most cases it is possible to write out the meaning of these acronyms without crowding the slide.

Finally, sum up at the end of your talk what you have achieved and what more might be required to completely answer your opening question or problem. The audience will typically take home one or two points you have raised in your talk. Do not expect miracles.

There is an enormous literature on powerpoints and lecturing, much of it more relevant to medical education than to biology. I have put together 8 specific rules for powerpoints and I list these here:

  1. Never use a dark background for your slides. The reason is that in rooms that have too much light, the audience will be unable to read white printing on a dark background. It is best to use black printing on a white or pastel background.
  2. Use at least 28 point font on every slide. If you think this is too large a font, project your lecture and go back 10 meters in a not-too-dark room, and see if you can read what you have written.
  3. Never have more than one graph on a slide. It is impossible to digest 4 or 8 graphs on one slide, and the audience can never read the labels on the axes.
  4. If you use colour on your slide for different lines or points, make the colours strong and check that you can distinguish them from 10 meters.
  5. Never use a table on a slide with more than 4 columns and 4 rows. No one can read most tables used in most talks because the font size is typically too small.
  6. Allow at least one minute to talk about what is the message on each slide. If you are giving a 15-minute talk, you should have no more than 12 slides.
  7. Do not use a photo as a background for a slide. Use photos as photos to make a particular point, and text as text. Do not in general put several photos on one slide.
  8. Do not use animation in your powerpoints unless you have already gotten an Academy Award for your work. If you need to use a short video, imbed it properly and test that it really works and is clear.

I think these two papers make additional points that are useful in developing lectures. Good luck and an early thank you from your audiences.

Blome, C., H. Sondermann, and M. Augustin. 2017. Accepted standards on how to give a Medical Research Presentation: a systematic review of expert opinion papers. GMS Journal for Medical Education 34: doc11. doi: 10.3205/zma001088

Harolds, J. A. 2012. Tips for giving a memorable presentation, Part IV: Using and composing PowerPoint slides. Clinical Nuclear Medicine 37:977-980. doi: 10.1097/RLU.0b013e3182614219

2 thoughts on “A Few Rules for Giving a Lecture

  1. Heikki Henttonen

    I would add one technical comments to the very good list above. Remember that 4 % of males are color blind, and cannot see red and green.

    Reply

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