Things you should (not) do in a talk

speechI always wonder how people regularly delivering talks for one decade or more can still run out of time in a conference, or show slides with so much information that the public just doesn’t know where to look at. Over the years, I learned a lot about what to do (and not to do) in a talk. I will share this knowledge in this and the next posts.

I think, things are getting better. I remember when people started experimenting with Power Point years ago (Yes, I was born in the overhead-projector age…). I saw aberrancies like black fonts on dark-blue backgrounds (serious!) or long 12-pt sized texts. Fortunately, everyone knows now that the only good background is white background and that fonts should be at least 18 points.

Not that my talks are perfect, but I take them very seriously and I’m always trying to improve. Perhaps this experience may be useful for you too. So, here are my tips.

1. Talking about Time

Let me start with the most crucial factor: time. Controlling the time is a matter of respect to the public and a sign of self-organization. If you have to rush through your last slides while the chairperson looks tired at you, the message that you are delivering is that you can’t organize a simple presentation. Then, how can I rely on you for developing a research project?

If your slot is 20 minutes, prepare a 15 minutes talk. If the slot is 30 minutes, prepare a 20 minutes talk. You have 1 hour! Don’t get greedy, stop at 40 minutes. More than that people just get tired and no one will be paying attention anymore.

This left-over time will be used for discussions, questions, and for any unpredictable events. If it happens that everything ends ahead of time–be sure–nobody will complain.

But how to control the time?

My rule of thumb is to prepare 1 slide/minute. For a 20 minutes slot = 15 minutes presentation = 15 slides. You should gauge your own time. Maybe your rhythm is 1 slide every 2 minutes. But be careful, if your rate is lower than this 0.5 slide/min, probably your slides contain too much information and need to be reformulated. I’ll come back to that later.

Counting slides helps, but there’s nothing better for having a real control of time than rehearsing. Do it at least once. Power Point has nice rehearsal functions. Use them. For an important occasion, rehearse several times and even gather some colleagues for a mock talk.

Don’t build your talk as a long single block. People’s attention spans are no longer than 10 minutes. Then, split your talk in several short 5 to 10 minutes blocks. Make the blocks semi-independent, in such a way that if someone sleeps through one of them, he or she can still came back and understand the next one.

Let me give you an example. These are the handouts of my last presentation in a conference.


I had a slot of 30 minutes. I prepared 31 slides, but from those, 8 are cover, back cover, and block titles. I spend almost no time on them (I know well my rhythm) and for this reason I count them as one. Then, I have effectively 23 true slides plus 1, which is good for about 24-minutes talk, leaving 6 minutes for questions. (In fact, I talked for 25 minutes in that occasion.)

Note how the presentation is split in 7 blocks. All of them together form a single story as I will discuss in the next post, but each block of 3 to 5 minutes is relatively independent. If someone miss one, the person can still catch up with me in the next block.

Final tips to cut the fat (I will elaborate more about them in other contexts):

  • Do you really need an Outline slide?
  • You’re talking to a public of specialists. Is your long introduction on the topic necessary?
  • Don’t ever leave slides to jump over if time rushes! (Sadly, I know people that do it.)
  • Some presenters (these gadgets to control slides at distance) have vibrating-alert functions. You may consider to get one of those.
  • Keep the answers to questions short.

* * *

So much for Time. In the next posts, I will discuss other aspects, like talk content, slide preparation, and how to address the public.


  • If you enjoyed this post, follow the blog by signing up in the sidebar. Leave your comments or like below. You can also follow me on Twitter.
  • Do you have other tips to keep time under control in a talk? Share with us.
  • The painting at the top is the Konstantin Yuon’s “The first speech of Vladimir Lenin in the Smolny“, 1935.

Categories: Productivity, Work Organization

Tags: , , ,

8 replies

  1. Nice series of posts. Note: your example with “each block of 3 to 5 minutes” does not fit into the above advice to “split your talk in several short 5 to 10 minutes blocks”.


  1. Things you should (not) do in a talk – Part 2 | Much Bigger Outside
  2. Things you should (not) do in a talk – Part 3 | Much Bigger Outside
  3. Things you should (not) do in a talk – Part 4 | Much Bigger Outside
  4. Should all theses be publishable? | Much Bigger Outside
  5. Still about boring papers: acronyms and abbreviations | Much Bigger Outside
  6. Expressions banned from my papers | Much Bigger Outside
  7. Yes, You Do Have a Thesis | Much Bigger Outside

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