Recently my PhD student gave a rehearsal of their 20 minute oral presentation. It was ok. Average.

In other words, (seemingly) long, and boring. Like so many people’s technical talks. What can you do?

What you can do is follow these simple rules I’m going to give. They’re not all my own, you can find most elsewhere. The problem is, most people think they’re impractical and don’t follow them. Result? Bo-ring!

Let’s call my student “Sam” (not their real name). The first mistake Sam made was to waste a slide giving their name and affiliation, which everybody knew. So the first rule is:

1 – Don’t waste the audience’s time telling them things they already know.

“But”, I hear you say, “slides are cheap!”. No they’re not. You pay in  terms of the audience’s attention. You start with a certain amount, and if it drops to 0, they stop listening. 

My late dear friend Ed Ashcroft told people about “Ashcroft’s constant”, which, he’d tell us, was eight. Eight what’s? Eight is the maximum number of slides you should give in a talk, whether 20 minutes or 50 minutes.

When I told Sam about this you should have seen the look on their face. I’m sure they were thinking of 20-30 slides. Think of the preparation!

Actually, if you follow my rules you might get away with 12. At the most, So the second rule is,

2 – Present at most 12 slides, no matter the length of the talk

Again, this seems impractical, but the rules will eliminate many slides.

The second mistake Sam made was to waste another slide with an overview of their talk. You’ve all seen them, “Introduction, Background, Objectives … Conclusions”. There’s no real information here, it cost Sam a lot of attention, and sent the message “this talk is going to be tedious”. So

3 – Do not have an overview slide.

To make things worse, Sam then proceeded to read the overview slide (while people started looking at their watches). This violates the rule about telling the audience what they already know – the overview is right in front of them. Also, it violates a more general (and very important) rule, namely

4 – Do not read text from a slide.

There are many reasons why this is a very bad idea. It means telling people what they (now) already know. It means giving the audience two forms of the same information. Invariably, their brains will compare the two forms looking for a difference. Or ignore them both. It means you as a speaker will invariably look away from the audience and look at the slide. Disastrous.

Sam’s talk was about analyzing Lucid programs. The next slide should have been an actual program. Instead it was more text about the analysis – read by Sam, of course. The relevant rule is

4.5 – Visual, visual, visual

Pay no attention to people who claim “I’m not a visual learner”. Everyone with functioning eyesight is a visual learner.

For example, Sam could have left the program up and talked about various properties of Lucid. And explained the statements. And the kind of analysis required. And the difficulties involved.

The best part of Sam’s presentation was a slide of a dataflow network (a simple one, to generate the Fibonacci numbers) which Sam explained, including the operation of first, next, and fby.

Given that you don’t want to present a lot of text, my general rule of thumb is

5. Make each slide an image or a quote, possibly with captions.

In general, people prefer (rightly so) examples over general rules. So.

6 – Present examples before general rules

And for heaven’s sake, keep the examples really simple.

7 – No complex slides, whether text or images 

The worst offenders are slides of mathematical formulas and equations. One math slide is ok, if the formula or equation is simple and in big type. Of course, if the talk is about mathematical research, more, simple math slides are allowable.

The last mistake Sam made was to go for 24 minutes, when they were allotted only 20 minutes.

8 – Do not ever, EVER, go over time.

It’s futile because your audience will be looking at their watches, wondering when you’re going to stop, rather than paying attention to you. Even if you’ve done well up to now, leave them wanting more. Did I mention, don’t go over time?

Well I eat my own dogfood. If this were a talk every rule would be a slide, and that’s eight. Of course these rules aren’t 100% rigid, but violate them only if you know what you’re doing.

My last word is, don’t assume the audience’s attention is infinite, don’t waste it, increase it.

And don’t assume a technical talk has to be boring!