People often ask, “How many slides should I use in a 20-minute (or 30-minute, or 40-minute, etc.) presentation.” I always respond the same way: “I don’t know. Maybe three, maybe 20, maybe 50, maybe 100, maybe none.”

There is no right answer. It depends on a number of variables, including the audience, the subject and the context. However, the number of slides in your presentation is less important than the way in which they are designed and used. I would rather watch a presentation with 50 well designed slides than one with 15 poorly designed slides.

Of course, you cannot disregard the time element. If you have 10 minutes and try to click through 500 slides, you’ll probably succeed in giving your audience a headache and not much else. You should use as many (well designed) slides as are necessary to enhance and support your message. No more, no less.

In 2010, I wrote a post on the same idea after reading an article by Seth Godin. I was prompted to revisit the issue after recently coming across a wonderful slide presentation on BBC News Magazine that is narrated by John Hockenberry, an American journalist and commentator who has been in a wheelchair since a car accident left him paralyzed.

In this presentation, Hockenberry shares the real message that people around the world should take away from the 2012 Paralympics that were held in London. The presentation lasts only three minutes but has, by my count, 45 slides. That’s one slide every four seconds. Yet not one of them was superfluous or out of place.

To see the presentation, please click the image below and you will be taken to the BBC News Magazine website. As you watch, notice how the images are used to enhance the words being spoken.

Image: Partial Screenshot of BBC News Magazine Website