Advice for giving a talk

What makes a good presentation?

I watch a lot of talks. Between monthly meeting of the Geological Society of Washington and professional meetings and student presentations and local departmental seminars, I see a lot of people present information aloud, with varying degrees of success.

I also give talks. While I don’t claim to be the best presenter in the world, I do know a good talk from a bad talk. I try to keep mine on the “good talk” side of the spectrum. Giving a talk, whether at a professional meeting, in a board room, or as just another day in class, is an act which is as much theater as it is information delivery. I’ve never taken a public speaking class, but I’ve got some real-world experience. Today, I’ve got some advice for anyone who’s going to be giving a talk. I’ll assume a traditional modern talk: a single expert speaker talking for half an hour or less, backed up by a PowerPoint slideshow. (“Expert” here means that you know something the audience doesn’t know. If that’s not the case, you might ask why the hell you’re bothering to give a talk in the first place.)

I hope the second-person style of this advice (“you, you you”) isn’t offensive to readers. Just imagine it’s an “open letter” to someone else, someone who you and I have just seen give a crummy talk.

Know what you’re talking about enough that you can speak extemporaneously. Reading from notes or an outline means that you (the speaker) are engaging with a piece of paper (or a laptop), and not with the audience. No notecards. You can use the images on your PowerPoint to guide your thoughts, but you should know the material, and the ‘trajectory’ of what you want to say, well enough that you don’t need some sophomoric crutch.

It should go without saying that one way to achieve enough confidence to speak extemporaneously is to practice: tell people at cocktail parties what you do, what topics you’re researching. Practice in front of the mirror. Practice in front of your spouse, your nephews, your pets. Practice with your peers, your professors, your students. Develop a full, robust taste for your presentation’s content that is independent of a particular string of words.

Look at people. Look your audience members in the eye, moving from person to person every few seconds. Do not talk to your PowerPoint up there on the screen. (Jess noted this in a similar talk advice post last September.)

Move around. The dynamics of a mobile speaker are much more engaging than a sessile speaker rooted behind some podium. I mean both waving your hands about, and physically walking around the room, forward and backward, left and right. Get close to people: like a magnetic field, human proximity is effective at making connections.

Use evocative language, including analogies, humor, precise vocabulary, pithy quotations, and the like. The spoken word is your medium, PowerPoint is your visual aide, and your expertise is your subject. Because you are delivering your explanations via the spoken word, you should use your words to sculpt a rich landscape for your listeners. Use active verbs like “wiggle,” “pierce,” “slam,” “jet,” “snap,” “rub,” and anything with a violent or sexual connotation. People pay attention to sex and violence; you can use these words as lures to draw them in to your subject matter. Also, vary the pitch of your voice. Anyone speaking in monotone clearly doesn’t care enough about their subject to get excited about it. The message to the audience is that they shouldn’t care either.

If you’re a ham like I am, then act it out. If you’re describing rocks getting squished, mime out being in a trash compactor. If you’re describing a cobble bounding downstream, jog a little slalom course across the room. If you’re talking about the position of dinosaur legs beneath their body (as opposed to say a crocodilian, where they stick out to the side), slump down on your belly and show what you’re talking about by contorting your own limbs in different positions relative to your body. Not everyone is comfortable with physical acting; some consider it demeaning to the dignity of the speaker, especially in staid, professional crowds. If so, that’s cool. But the audiences I have observed eat it up, professionals or not. It’s engaging and endearing.

It is okay to pause in silence while you gather your thoughts. Avoid nervously filling this pause with an “Umm” or an “Err.” Not only only are umms and errs 100% information-free, they ruin what could otherwise be interpreted as a dramatic pause, full of conscious intent. Good songs are not just a constant stream of words, they include slow bits and wordless bits and instrumental bits, all of which give the listener a chance to cogitate on their meaning. You’ll notice on “All Things Considered” or “Radio Lab” or “This American Life,” the producers insert little “buttons” of music, about 10 seconds long, in between information-rich pieces. Good presentations should be like that too, but unlike radio, you don’t have to worry about “dead time.” Your audience can see you, see your PowerPoint. They know you haven’t gone “off the air.” Better still, your pause gives people a chance to swallow your thoughts. Ramming information down their throats without a chance to chew it will not nourish them with your ideas.

Now for some specific advice about putting together a decent PowerPoint (or Keynote, or whatever) slideshow:

Use as few slides as possible to get your point across. Everyone is busy, and we don’t want our time wasted. Get to the point, and make it worth our time to be sitting there in your audience.

“Outline slides” are those that present your talk as an outline. (“First I’m going to give you some background on the problem, then I’m going to tell you about our research approach, then I’m going to interpret our results in terms of the dominant paradigm.”) In my opinion, outline slides are a waste of time. Clearly, any effective presentation is going to supply necessary background, describe what is unique about the presenter’s approach, and conclude by tying it back into the big picture. You don’t need to waste our time by outlining it for us. No decent movie or television show (including those about science), starts off with an outline! A shared outline is redundant to a well-constructed talk. If you’re a unsophisticated enough presenter that the only hope of communicating your intent is to repeat it via outline, then you shouldn’t be talking. Shut up and go back to your office; write it all down as a paper instead.

Use as few written words as possible. PowerPoint should be used as a slide projector: It is not an outline (or worse, a transcript) of what you intend to say. The worst presenters type out what they want to say, then read it aloud off the screen. This is an abomination of presentation. It is the antithesis of engaging your audience with your expertise. Ideally, all your slides should be imagery. There should be no slides of just text.

Use pictures. Use photographs. Use cartoons. Use graphs. Use data tables. Show movies. Show animations. Use visualizations. PowerPoint is a visual medium: use it for what it’s good for. Use it as a slide projector.

No sound effects, no fancy slide transitions, none of that stuff (“phluff,” as Edward Tufte called it). …Good lord, do I really even have to say that? Unfortunately, I think I do. I have observed people (students and bureaucrats, mainly) sometimes use these “bells and whistles” with what I suspect is an intent to distract the audience from a lack of content. Use of these features is an insult to your audience. No “clip art” either.

Use images at sizes at or below their inherent resolution. (i.e., not at sizes above their resolution.) In other words, if you find an image online that is good for your talk that measures 200 x 300 pixels, do not blow it up to 800 x 1200 pixels. It’s going to look horrible if you do that: pixelated and grainy and incredibly bad. I have seen some of the scientists I respect most give talks with these sorts of graphics — it looks like something a sixth grader might have thrown together. I find it shocking that someone so skilled in one aspect of their professional life could be so completely clueless in another. Even if you’re not capable of generating your own graphics, have a little bit of aesthetic sophistication.

Number your slides. If your presentation has 20 slides, your first one should have “1/20” tucked down in a lower corner, somewhere unobtrusive but obvious to anyone who’s wondering how much longer you’re going to go on. The second slide should say “2/20,” and so on. This gives your audience an orientation to your intended talk length, and they can then decide whether they want to keep sitting there, or whether their time would be better spent off getting a cup of coffee. One of the first things that I always do when I am watching someone set up for a talk is to steal a quick glance at their total number of slides. If they’re going to attempt to get through 55 slides in 20 minutes, then I know that either (a) they’re going to be going too fast for me to absorb the slides, or (b) they’re not going to be finished on time. A general rule of thumb is one slide per minute, though that’s flexible depending on your content and speaking style. Notice that numbering your slides does not do any good if you don’t say out of how many total that number is. In other words, seeing a “6” at the bottom of your sixth slide doesn’t help me estimate when you’re going to be done with your talk. (“Is that 6 out of 7? Or 6 out of ∞?”) Not that I’m not interested in what you have to say — but it’s unlikely I’m going to be rapt by your talk, smart as you are. My brain is going to be thinking about other stuff at the same time. Work with me here! Give me a sense of your plan for the next 20 minutes of my life.

End it cleanly, decisively, and preferably a little bit on the early side. Let us know that you’re done without saying, “Umm, …and that’s the end.” Think about the end to the most satisfying entertainment you’ve absorbed lately: a film, a song, the latest episode of LOST. You know it’s over without them having to spell it out by saying “…and that’s the end of this movie.” Asking what questions your audience has is a good fall-back ending statement, if you can’t think of anything more clever. Notice I don’t say “Are there any questions?” I say “What questions do you have?” Your expectation should be that your opus generates insightful, chewy interrogatives from those privileged enough to hear it. Clearly, any talk worth spending the time listening to should generate some thinking, some feedback. If it doesn’t, that’s a major red flag that you haven’t engaged your audience with your material.

OK: I’ve given all my advice to our nameless third-person lousy speaker. What else would you tell them? Chime in via the comments section below.


21 Responses

  1. You hit the nail right on the head!
    But it’s not just the scientists…. I’ve seen every possible mistake that you enumerate committed by professional trainers.

  2. I agree with this excellent guide

    On the clean end, a conclusions slide (unlike an aims slide) is often worth while. Pick three things that you want your audience to go away remembering. Express each in six words or fewer. (You don’t have to spell it out on a slide, you could talk over a nice image).

    As well as having a clean end to your presentation, have a clean start. Script and rehearse your first two sentences. Once you are through these you should be able to extemporise from here. It does help to get over any initial nerves.

  3. “outline slides are a waste of time”

    Yes, a world of yes. I am so sick of people wasting a tenth of their presentation time during class seminars by telling us what’s coming up in 2 minutes time.

  4. On the topic of outline slides, whilst I agree that you shouldn’t **display** one, it should be part of your preparation for the talk.

    A good talk is a narrative driving towards your conclusions. Compiling an outline slide does help you focus on the structure talk and focussing in on what it is that you want to say. Once you have completed the powerpoint and ensured that your presentation conforms to the structure, then you can delete the outline slide as it should now be self evident.

  5. Ian:
    Absolutely! Compiling an outline, whether within the framework of PowerPoint, in a Word document, or on a bar napkin, is essential to any narrative: a presentation, a paper, a blog post…

  6. Fancy sound effects, transitions … add to this list highly complex or variable slide backgrounds. Powerpoint and Keynote are bad for this, because their templates try to steer you to using gaudy backgrounds (in fact, many of the things Keynote and Powerpoint would recommend make for terrible presentations). The slide background doesn’t have to be a solid color (although that’s generally what I use), but it shouldn’t be the focal point of the slide.

    On a related note, when you have to use text, make sure it’s legible. Make it big and simple, and be sure that it’s a color that contrasts with the background so it doesn’t get lost. Avoid fancy fonts that are difficult to read.

    If possible, practice your presentation with an actual projector; some things that seemed like a good idea on your laptop screen just don’t work when they’re the size of the wall.

    There are several things that can really screw up a slideshow from a technical standpoint, because of incompatible formats between different versions of Powerpoint. These include animations (which you should avoid anyway) and image and video files. If possible, dry run your talk on the actual equipment that will be used. If you can’t do that, save your presentation in both the current version of Powerpoint, and one version older (and confirm that the older version works). That way if the presentation computer isn’t as up-to-date as your own, you can still use it.

    That problem can be more severe if you’re using a Mac; PP for Mac seems to handle a much greater variety of file formats than PP for Windows, so if you’re working on a Mac but presenting in Windows make sure the Windows machine can handle the file.

    • Alton’s on target: I had forgotten how bad gaudy or low-contrast backgrounds can be! However, I don’t think there is anything wrong with animations, per se. It’s certainly true that they are QUITE prone to technical problems, but if these problems are solved, animations are a terrific way to convey information. They communicate dynamic ideas well to those who cannot picture three-dimensional motions well, and they’re a great way to rapidly demonstrate the effects of geologic time on a landscape.

      • True on animations; I was thinking of the complex and often unnecessary things that are built into Powerpoint, and that don’t actually add information (taking 5 seconds for an arrow to make its way onto the screen, just so it can point at a static object, for example). Animations that actually convey information are fantastic (when they work)!

      • Gotcha! Yeah, those “animations” suck.

  7. Unfortunately, though generally agreeing with all the points you mentioned, I have to disagree on including humor in a presentation. Being a fan of including a few, humorous points myself, I only had bad experience with it. That also includes other presentations given by other students at university. Simply including a funny mammut in front of a glacier (as the introduction screen) for a talk on the ice ages already got me critizism of giving a “mickey mouse”-talk, on other occasions the humorous approach also resulted in harsh critizism by professors along the lines of, “we are doing serious business here” and “not in disney land”. On average talks presented by me or others with humor or jokes scored worse than those without any humor. So, speaking from university experience, students better not try to be funny. Sadly. As I like it.

  8. Nice one, Callan. Great advice…especially the crawling on the floor part.

    I don’t think the outline slide is fatal, however, unless it is laughably simple. For one thing it is a promise for what you plan to cover and thereby a metric as for whether you succeeded. It may also help if your title does not telegraph an implicit structure. I do see your point, though. It is sort of a tautological device.

    As for humor, I agree with you and disagree strongly with the Lost Geologist’s comment. A small to even medium degree of humor is almost an essential component to maintain interest and remind everyone that you are a real person. If it offends someone, so what. Seriously, something is always going to offend someone. If I can’t have a little fun in a talk, then I don’t want to give it. Using a bit of humor is far more memorable than trying to be a cold and clinical scientist. Most geologists are pretty open minded about this.

    If someone judges me negatively for taking a stab at a humorous aside in a talk that is a risk I am willing to take. So far in life I have landed two good jobs with talks that have certainly had a joke or two in them.

    Anyway, I am an irrepressible wise-ass and offend people all of the time…why stop just because I am giving a talk? Remember, drjerque is faux french for Dr. Jerk.

  9. Awesome post. I had done a similar post after GSA ( (I hate it when people link to their own stuff but hey, whatever) but you caught a lot of points that I missed. I agree the outline slide can be a bit superfluous and I like your comment about numbering of slides. I always liked it when I see it but I can never remember to do it myself.

    And I am one for humor. I always have a habit of inserting a joke or random comment here or there to see if I get a chuckle from the audience. I often do the same thing when I am teaching so I don’t see a difference in a presentation. Although I am a wise-ass as well.

  10. I would also say, learn to speak with a microphone. Use your real voice and put the microphone where it will (1) pick up your voice and (2) avoid the air coming out of your mouth and nose. If there is no microphone, speak to the back row. Have a glass of water handy, and use it.

    • Excellent point. The quality of the voice, and its volume, is essential as well. Andrew’s comment reminds me of another pet peeve — over use of the laser pointer. It is unnecessary to use the laser pointer’s glowing dot to show us the words that you are reading aloud to the audience. It only makes it that much more obvious that you’re reading words aloud rather than discussing. Also, I’ve seen people essentially dance the laser dot all over the screen rapidly, inducing a feeling of vertigo and nausea in weak-stomached audience members. Finally, if you’re nervous, or if you were out too late the night before, your laser dot will twitch erratically if you try and hold it in one place. This can be cured by either (a) walking over to the screen and pointing with your finger at the location in question, or (b) bracing your laser-wielding hand against something more solid, like your hip.

  11. Excellent!
    “Like a magnetic field, human proximity is effective at making connections.”

    Really enjoyed this. As a presenter you are always going to want the audience member to leave with the message and scatter it about like seeds. I think people underestimate how important it is to make that connection to your audience to further your cause.

  12. Excellent post. As the (perhaps) rare geoscientist with experience in graphic design and moviemaking, I’d say you’re spot on. Except I disagree on “fewest slides possible:” if you’re a good presenter and have very good graphics and photos, you can go 30-45 seconds per slide average. For long talks (>15 min) in workshops, I think *careful* use of helps.

    Your slide numbering idea is wonderful.

    Especially if you have a little stage fright, just memorize your introduction–yep, write it out and even better record the audio, put it on your iPod, and listen to it on the drive/flight. No matter how good you are, having that first minute or so more down pat will get you off to a great start, build your confidence in that critical first minute, and totally grab the audience’s attention–“hey, this is a smooth talk!”

    Never use more than one photo per slide unless you’re comparing the photos! I see talks now with as many as four semi-related images on them. Horrible, distracting.

    Hypocentre’s right about having just a few points you want people to remember.

    Study Tufte–use those nice beiges, black, white, brown, brownish yellows he favors. The eye loves them. And amen on the animations–forget all the junk PP encourages you to use–finding the right colors is not easy and PP fights you the whole way. Run a black or dark brown bar across the very top or bottom of your beautiful photo, and add white text.

    Callan, how about a gallery of slides? I’d love to contribute! Great post.

  13. Inspired by your post, I’ve put some examples and links on Riparian Rap:

    • Thanks for those examples, Steve. I remember when watching your GSA talk how you were effectively using humor to make your point (about scaling relationships, and how old Japanese monster movies looked fake because of them), and also annotations. I love annotations, and your Godzilla slide is really well annotated. Yeah, I’d like to compile a list of the best and the worst slides for discussion. Maybe in a future post?

  14. Really nice post–you hit almost everything that I try to stress to our undergrads about giving good talks.

    I do agree with some of the comments about slide background & font color–dark backgrounds with light script are easier on the eyes when sitting in a darkened rooms. And make sure the text is large enough to actually read!

    Another pet peeve of mine is when images & diagrams are included, but are not referenced in any way, shape or form. If you created the diagram yourself, that’s fine, but if you modified it from someone else or just “borrowed” it, please include where it was from!

    And my final comment: I had a wonderful professor at Iowa during my PhD who knew exactly how to turn an ok talk into a great one. Her philosophy was fairly simple: while showing your opening slide, give a short (1-2 minute) summary of what question your going to tackle, why anyone in the room should pay attention, and a broad idea of what your going to cover. At the end, take another minute to tie-back in with this opening statement and remind people of what you’ve covered & why it was important.

    I never saw the numbering idea before–I’ll have to add it into my repertoire :)

  15. I had a teacher who quoted the saying that a picture is worth a thousand words and added that a coloured picture is worth ten thousand. I see Powerpoint as even more than a projector – it’s graphically powerful in its own right (yes, ignoring all the preset backgrounds and other wizzbangs); combine it with Photoshop or whatever, and the results can be stunning.

    I don’t know what to add to your post – it should be required reading for anyone who has to give talk.

  16. In your example for an outline slide, it would be a waste of time. What about if you have 6, 8, 10 or ____ points? Doesn’t it make sense to given an overview? And do you mean only no outline slide or no verbal outline/overview?

    With respect to 1 minute per slide: this is good tool to use even if you do not actually use slides in the speech. By that I mean, if you have been allotted 20 minutes you can prepare by creating 20 slides or 20 pages in a word processor using slide-size font. Then when you practice you can amend as appropriate.

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