Tuesday, September 20, 2011

Rules for giving technical presentations

This is an update of an old post, from nearly two years ago. Technical presentations have not improved in that time.

I have attended a lot of conference, scientific and technical presentations, and a significant proportion of those were pretty bad. Another large proportion were mediocre at best, and only a few were pretty good. From what I have observed, and from talking with other presenters, I have formulated the following general rules for giving technical or scientific presentations. While none of these rules are inviolable, please do at least give them some thought the next time you give a presentation.

General Rules

There are two general rules – most of the specific rules come from these two.

1. Don’t waste time, either yours or the audience’s.

2. Don’t insult the intelligence of your audience.


Specific Rules

1. If you have just been introduced with your name and the title of your presentation, don’t repeat this information. You may have them on the first slide, in fact this is probably a good idea, especially if that slide has your email address prominently displayed.

2. If you are presenting to a specialised audience, leave out the background material. For example, if you are presenting to a conference on evolutionary computation, spending even one or two slides explaining what evolutionary computation is violates both general rules.

3. If you have long sentences on your slides, don’t read them aloud. This violates both general rules. It is better to not have long sentences.

4. Outline slides are not necessary. They waste time and assume that the audience isn’t smart enough to notice what you are currently talking about. An exception to this is for long presentations, like hour-long seminars: in this case, it can be useful to repeat the outline slide at strategic points in your presentation. This is to show the audience what part of the talk you are up to, and what they can expect next. Often, different people will be interested in different parts of your talk, so doing this lets them know when they should pay attention.

5. Don’t place equations on your slides unless they are absolutely, positively and irrefutably necessary. If the math is complex enough that it needs to be explained, then it is unlikely that the audience will be able to parse it fast enough to be useful to the presentation. If it is simple, then it can be left out.

6. Know the length of your presentation. A good rule of thumb is an absolute maximum of one slide per minute of presentation, including title, summary and conclusions. Thus, for a fifteen minute presentation, fifteen slides is a good count, ten is better, less than ten is best.

7. Keep to the point of the presentation. If your talk is on bioinformatics, I don’t want to hear about your university’s teaching computer lab.

8. Proof-read your presentation. Use a spell checker. Have someone else check your presentation. If English is not your first language, have it proof-read by someone who is a native speaker. Try to avoid common grammatical errors (infer/imply, affect/effect, explicit/implicit, and so on). Know what words like "literally" actually mean (Jamie Oliver, I'm looking at you!).

9. Know your presentation material. If you have to stop talking to work out what something on a slide actually means, you are wasting everyone’s time. It also makes you look like an idiot.

10. If you are presenting a group of numbers, use a plot of the values, rather than a table, especially if the intention is to compare and contrast the groups. Be careful with the use of colours! A non-trivial proportion of the population can't distinguish between red and green. Be aware that pale colours, such as yellow, can't be seen easily when projected.

11. Moving about is good. Moving energetically is even better. A presenter with physical vigour commands more attention from, and inspires more energy in, an audience than one who stands still, or worse, sits while speaking. That said, moving around like your feet are on fire is distracting. Use your best judgement.

12. Make eye contact with your audience. You should try to make eye-contact with each member of the audience at least once during your presentation. They are here to listen to you speak, so you should acknowledge their existence by actually looking at them. That said, constantly looking at one particular member of the audience is likely to make that person feel uncomfortable.

13. If you cite published work, you must include enough information for audience members to find it! A citation in your presentation like Watts et al (2011) is absolutely useless on its own. At a bare minimum, you would need Watts et al (2011), Ecological Modelling. At least then someone has a chance of finding the paper.

14. Change media regularly. Write on the whiteboard. Show a diagram. Play a video. Hand around a piece of equipment. Anything that is a change from words on a slide.