What makes a great scientific talk?

By David Winter 06/04/2011 12

Genetics Otago (the group behind the Southern Genes blog at sciblogs) runs a bi-weekly meeting for postgrads to catch up, find out about each others work and perhaps even learn something about life as a budding academic. Next week I’m going to present a short talk on… how to present a short talk.

Looking about for some resources around the web, it seems most just reinforce the preferences of the author. To try and be a little more representative in my approach I’m going to present the notes I’ve written for my talk so anyone with an opinion can tell me what I’ve missed and what they think I’ve got wrong. This is going to be presented to postgraduate genetics students, but most of the skills that go into making a good presentation apply beyond genetics and even science, so I’d welcome feedback from anyone.

(As new tips come in, I’m adding them in italics)

Think about your audience, then tell them a story

You might know all there is to know about the protein family you study, the amazing new phylogenetic methods you used or why finding the mutation that underlies the phenotype you are studying will change the world – but does your audience? As a postgrad you’ve become an expert in a very narrow field, but you’ll hardly ever talk to an audience in which everyone is as clued up as you are. Be generous and share some of your knowledge, think about who comes to the sort of talk you’re presenting (you lab? your department? an inter-department program? the public?) and think about what they already know, what terms they’ll be familiar with, and what sorts of data and results they’re used to interpreting.

It seems bizarre that I should have to mention this, but you should also think about what sort of thing the members of your audience care about. You hardly ever get a chance to talk about all of your research at once, so when you prepare a talk you are always making a decision about which details to include. Think about your audience when you decide the ‘angle’ you want to take in your talk; are they specialist your area will be interested in how you applied a bleeding edge technology to your problem? Or are they wider audience, who are more interested in how your results will be translated into practical benefits? (That last angle is a little harder to work if you study speciation in land snails).

Once you have your angle, and you know the level at which you will pitch your work, you’re well on the way to the single most important tip for any presentation: tell us a story. A week after you’ve given your talk, no one is going to remember the degree to which transcript NM_091299.1 was over-represented in your second experiment, but if you told them a really good story about how you found out how a certain gene plays a role in a disease it will stick with them. So how do you tell the story…

Whatever you do, don’t open powerpoint now

I couldn’t care less what software you use to present your story, you can make awful presentations in prezi and you can make wonderfully clear ones in powerpoint, but the worst thing you can do is start writing you presentation in powerpoint. As soon as you sit down in front of that program you’re sucked into making those bullet point lists:

  • Capulets and Montagues
    • Alike in dignity
    • In Verona
    • Ancient grudges
      • led to new mutiny
  • Romeo and Juiet
    • From these loins (C&M)
    • Star cross’d lovers
    • death marked love
      • buried their parents’ strife

There might be some sorts of information that are best presented in this way, but certainly not the whole talk. More to the point, most people use these lists to mark out the structure of their talk. That’s not what slides are for. The slides are their to illustrate, back up and reinforce the things that you are saying and to present your results once you’ve prepared your audience for them. At the moment you should be worrying about the story you’re going to tell.

Stories have structures, and almost all good scientific talks follow a similar structure. They start with a broad outline of the field you studied (tailored, of course, for the audience you are talking to) which narrows in on the one bit that you are working on. It’s nice to end this introduction with a clear statement of the questions you’re asking: “what genes get turned on in queen bees but not workers”, “what, if anything, is a rabbit?”, “Why are some sheep more resistant to parasites than others?”. Then you present the results that hopefully answer the question, before finally stepping back and showing how those results have changed the big picture you presented to begin with. It goes without saying that you need to be careful and precise when you are describing your results, “telling a story” is not another way of saying that you are free to throw in wild speculations or ease over wrinkles in the data.

Take some time to design your slides

You could spend a whole session on information-design and scientific data (I contributed to one last week!), but the most important points are pretty obvious. Make all your slides clear. Don’t spend hours worrying about the particular font or colour combo you use (light on dark is fine, as is the opposite) just make sure everything you present is legible and nice to look at. Don’t use esoteric fonts, because they probably won’t be on the computer you use to present your talk. Do proof read your slides (I’m terrible at this, and really should get other people to do it for me).

Often, cartoon style diagrams or illustrations help you explain complex ideas quickly. When it comes to graphs and data, you should really think about each element of the figure and decide whether it needs to be there to convey the point you are making: does anyone care about the precise value of the probabilities on your giant phylogenetic tree? Do you need a legend for your bar chart, or can you directly label the bars? You don’t want to end up saying “I know this is hard to see but…” at any stage (that includes pie-charts of your 154 GO terms, use an ordered dot plot or bar chart instead). If you use colour, be aware about 7% of the males in your audience will be red-green colour blind, you can use one of these palettes and check your resulting graphics here.

If you are presenting the same comparison in multiple slides (wild type against mutant, or one species against another) keep the colours consistent from slide to slide. There’s a lot more that could be said about this, I’ll add links to some great resources on information design below.

Give you slides decent, descriptive titles (“Mutant is 100x less effective than wild-type”, not “Alleles compared”)

Practice your talk

Another one firmly from the “I shouldn’t have to say this” category, but how many times have you been to a seminar that ran 20 minutes over time? Despite anything else, it’s incredibly rude to turn up to a presentation without having rehearsed it, especially if you’re at a conference in which your overflow eats into someone’s time.

Rehearse your talk out loud, and preferable to a test audience.

You should consider your notes and your first set of slides as a first draft – something to be pared down into a tight presentation that you know inside-out by the time you present it. The challenge here is how to do that and still sound fresh when you present…

Be an incredibly charismatic and dynamic presenter (or just yourself, actually)

Everyone will have their own presentation style. I’m one of those people that talks a thousand miles per hour, walks about the stage and waves his hands. Some people think that’s a presentation skill, but, really, I’m just a big science fan-boy and I can’t stop myself. If you’re not that sort of person, then there’s no point pretending to be, and you can present a great talk without running around like a fool. But there are a few things you can do to to keep an audience interested in what you’re saying.

Don’t rote learn every line of your talk

It’s much better to have a few key points or phrases you want to get to and a good idea of how you’ll navigate between them that to present a dreary mantra. Knowing where each passage is headed also prevents that very kiwi trait of adding an upward inflection to each sentence, which doesn’t fill anyone with confidence! You’ll likely be nervous when you start your talk, knowing exactly what you’ll say in the first few minutes will let you ease into the talk and feel confident once you move into the body of the talk.

Know what’s on your next slide

This is a really easy and effective one, if you start talking about the next piece of data in your talk before you actually present it you are able to prepare your audience for what they’re going to see, and you don’t take their attention away from what you are saying. The “Presenter tools” feature in later versions of powerpoint lets you see the next slide (and a timer) on your screen.

Take a breath either side of presenting something cool/weird/important

Just like it says, use a little bit of silence to underline the things you really want people to remember. If you have a really controversial or counter intuitive point to make, think of a short sharp sentence that describes it, take a second to let it sink in then start explaining why you think it’s true.

A pointer on pointers

A nervous presented makes for shaky hands, and shaky hands and laser points really don’t go together. I personally like the big-pointy-stick method (as displayed by the wonderful Hans Rosling in his TED talk) if the screen your presenting on is small enough. Alternatively, you can rest your ‘pointing hand’ on the dais, or use the mouse to highlight sections or even draw on your slides during your talk.

Be confident

You know what your talking about, really, you’ve done a literature review and you’ve collected all this data. A lot of younger postgrads suffer from a sort of imposter syndrome: they think they’ve somehow snuck their way through an undergrad course and into a scholarship and PhD program without anyone noticing they don’t have a clue about what they’re doing. This lack of confidence is manifested in two ways: people either present their data apologetically (“I think…”, “…or something”, “but I don’t know”) or they go to the other extreme and drown their message in jargon, as if they were proving they too can wield these words, just like a real scientist. Neither of these are approachs are a good idea; if you don’t believe your conclusions why will anyone else, and too much jargon will leave half the audience behind.

Leave time for questions, and be honest in answering them

Of course, you should leave time for questions and of course it’s much, much better to say “I hadn’t considered that, do you want to talk about it later” than to extemporise a wild and whirling answer to that guy that just has to ask the really mean question.

In powerpoint, typing the number of a slide then pressing ‘enter’ lets you jump to that slide. If you remember the number of “the big data slide” in your presentation (or write it on a post-it), you can skip write to it when you are asked a question about it and look like a pro.

Have fun, and ignore what I said

Don’t get too worried about all these rules. If you understand why they might be helpful in some cases, then use a little judgment and decide if they work for you. It would be great to see a talk that doesn’t start with a broad introduction, but instead a single slide showing the most important result to come out of your work. From there you could work back, and try and convince your audience that the slide really was worth it’s place at the start of the talk.

Presenting is an important skill for a scientist, and if should be one you try and develop through you career. When you go along to departmental seminars and conferences, take note of the way people present their work. Learn what works and what doesn’t (especially note things that annoy you or waste your time, and try and avoid those!)

Remember, I want your ideas on how to make my advice better!

Here are some links with tips on designing charts/diagrams/illustrations (feel free to suggest more):

12 Responses to “What makes a great scientific talk?”

  • Thanks David! – excellent and supremely useful post, especially the comments about using silence to best effect. I would just like to add, for anyone that is in the market for this sort of thing, that over at http://mesa.ac.nz/?page_id=491 we (Graduate Students from MacDiarmid Institute) have put together something similar. However, we also have large sections on good FREE software to use that get you out of bullet-pointing habits as well as some tutorials on how best to use them to really add visual impact to your presentation :)


  • I very much enjoyed this, and like your idea of telling a story before launching into the slides. I am thinking of doing this in my next conference talk, and maybe also in teaching.

  • Great advice. Thanks!
    Regarding laser pointers – it really freaks the audience out if the presenter is flapping his arms around forgetting that his pointer is on – everyone gets scared their eyeballs will fry when the beam hits them and they stop listening to the presentation. Also, when we get nervous or have too much coffee before our talk, the damn laser beam jiggles all around when trying to point at a special spot on a slide. Everyone starts thinking “thank God he’s not a surgeon!” … if possible rest your pointer hand on the dais just before you turn on the laser. They’ll be impressed with how cool and calm you are!

  • Also, having the little red dot jiggling around can be really irritating to folks in the audience. I tend to use the mouse pointer as the mouse is on a firm surface & it does away with jiggle completely :-) If I really want to emphasize something then I turn the arrow to a pen & underline/circle stuff.

  • I’ve always found that rehearsing a talk in an actual lecture theatre is good, as sometimes this is where you can more readily spot mistakes on the slides as well as bad colour combinations (which look good on a computer screen).
    Also rehearsing out loud weeds out phrases that might sound good in your head or on paper but which sound a bit naff when said out loud or which turn into tongue twisters.

  • “but the worst thing you can do is start writing you presentation in powerpoint.”

    Actually, David, I’m going to have to disagree with you here. I use powerpoint to bring my talk together. I insert key phrases, ideas and pictures, move them around,etc.
    However, the powerpoint I end up giving usually is completely different from my first draft.

  • You’ve penned a helpful, comprehensive summary. And appropriate to all science disciplines too. Thanks! Two additions to consider:

    (1) Re-evaluate whether a slide-driven talk/lecture is the most effective way to reach your goals.
    If you are giving your talk at a big conference, then, sure, a powerpoint-style slideshow is the only viable way to reach your goal of making you and your ideas be memorable. BUT if you are presenting to a more friendly crowd of less than 25 people, then stop and reconsider… would you be better off without slides? Is your top goal to get constructive criticism on a still-evolving project? If so, then consider basing your presentation on a few infographic-style pages (dense graphics & text). Print a copy for each audience member. You’ll often get more and higher quality feedback with this less formal, conversational, and interactive style of presenting. For more info, investigate Andrew Abela’s ideas and book, ie http://www.extremepresentation.com/crsbrs/ and http://www.extremepresentation.com/books/advanced_presentation_by_design/

    (2) Make sure your slide titles explicitly and concisely state the main point/result/assertion of that slide.
    Most presenters use a short phrase or single-word headline. A more effective approach is to write a longer, but still succinct _sentence_ that states the result. Adding more text in the title seems counterintuitive, but it really does work well when the rest of the slide has effective graphics and minimal words. For more info, see Michael Alley’s 5 min video and book, ie http://www.youtube.com/watch?v=d04w4vvByDI

    Other resources:
    Garr Reynolds – blog & books:
    Nancy Duarte – books:
    Scott Berkun – book:

  • Thanks guys, comments added to the ‘other’ atavism, will get sucked by sciblogs soon.


    Like I say, do whatever works for you, but next time you have a talk to prepare, start by writing some notes and sketching some ideas in a notebook, I think you’ll find you’ll be much more free in the ideas you come up with that way.

  • Here’s a tip I have found useful:
    The very first words out of your mouth should be “Good morning/afternoon/evening, my name is John Smith and thank you all for being here to listen to my talk about Why I Like Rainbows.”
    This piece of filler marks the start of your talk, in case your audience is still busy chatting. It gives them all a few seconds to adjust their listening, to adapt to your accent (especially important if English (or whatever) is not your/their first language). It also gives you the chance to shake off any last-second nerves and adjust your speaking (pace and especially volume) before getting to the words that actually matter. Even Shakespeare used to “waste” a couple of lines on irrelevant material to mark the start of his plays, when a loud and distracted Elizabethan crowd could be wrenched into attention without losing out on important plot points.

    Also, a strong, memorised closing remark, ending on “thank you for listening.” marks the end of your talk (signposting is as key in a talk as in an essay) and means you won’t look like you’ve just sort of come to the conclusion of your talk… and kind of ended up running out of things to… err… say.

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