The Value of Scientific Presentations

In conferences, I often come across science that is great. Results are amazing, people have done something that was thought not to be doable, or they have built a system that has incredible properties.

However, that same science is often presented in a way that makes it clear that the presenter has more confidence in his science than in the presentation.

Now you might say, “the science is complex, then the presentation of that science can also be complex”. But that is not true, because the purpose of a scientific presentation is not to educate the audience about the science; the purpose is rather to convince the audience that you have done something cool and that they should read the paper. In other words, once you’re on the podium, you’re an advertiser and no longer a scientist.

If you look at a presentation from this angle, a lot changes. You should

  • Explain the problem in some detail, so that the audience can understand why you spent time solving it.
  • Make a simple and forceful argument, simply because this is more likely to be understood by an audience during a presentation. This might mean leaving stuff out. In fact, it will mean leaving stuff out.
  • Present a high-level view of the work than in any particular detail, since the details are in the paper and are hard to follow during a presentation.
  • It’s OK to oversimplify, as long as you say so. People can always read the details in the paper. For example, in one presentation of mine, I presented a diagram, saying “you don’t need to know the details here—you can always see those in the paper—but the important thing is that stuff that’s to the top and to the right is better”.

From this view you can derive immediately some rules of thumb:

  • Don’t put formulas on slides, unless you’re a theoretician and present a fundamentally formulaic result. Even then, make them simple.
  • Take one concrete example, explain it in some detail and use it throughout the presentation to illustrate your method.
  • Have rather fewer slides, even if it means leaving stuff out.
  • Speak slowly. Anything that forces you to speak at a rate that’s faster than normal speech must go.

Other things come from cognitive psychology. For example:

  • Most people can either read or listen, but not both.  Since you will be talking most of the time, it follows that expecting your audience to read what’s on the slides while you’re explaining something won’t work. That means that you should work graphically most of the time. Use little text.
  • Most people will not be able to remember a long and convoluted argument. Therefore, simplify.
  • Most people understand stories, so make your presentation a story. The Jabberwock threatens the village (there is a serious problem). The villagers try all kinds of stuff that doesn’t work (current techniques don’t solve it properly). Along comes the hero with the Vorpal Blade (this is my cool technique). Vorpal Blade goes snicker-snack, beheads the Jabberwock (my technique solves the problem). Hero galumphs back with head (I show you evidence that it works). The End. Or is it… (future work)? (The use of Jabberwocky is due to Andreas Zeller.)

After you’ve done this for some time, you will probably see your research itself in this way. “Can I find a simpler argument that would prove my case?” — “What problem precisely am I trying to solve here, if I can’t state it in a sentence or two?” I consider this to be a good thing.

Oh and another thing: good presentation skills, like writing skills, come easily to nobody. You must practice and continually improve.

So go out and impress people not just with your cool science, but also with your cool presentations.

[Update 2011-10-12: Added attribution of the use of Jabberwocky.]

About Stephan Neuhaus

Stephan Neuhaus has been working in security since 1992, when he was a member of the PGP 2.0 development team. He has since been a successful entrepreneur before going back to University where he got his PhD in Software Engineering from Saarbrücken University in 2008. He is now a Senior Researcher at ETH Zurich, where he works on empirical software security in Prof. Plattner's Communication Systems Group.
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