In this page, I will describe a method for making effective academic talks that you can almost always use. The idea is to give the main points of your talk as early as possible, without going into details, to attract the audience right away, rather than holding off until the end. I learned this method from Dr. Michelle Strout during my PhD at Colorado State University, and have been using this method for pretty much every single presentation I have given since then.
Although I haven't heard anyone else call it the punch-line method, it is not a new idea. If you look at A Generic Conference Talk Outline by Mark Hill, the very first slide is the forecast, where you give the one key idea to walk away with. This is the spirit of punch-line talks.
In the ideal world, your audience may politely listen and give full attention to your talk. However, you can never expect this to happen in conferences, as many of your audience have a lot of things to worry themselves, such as making slides for their own talk the day after.
Therefore, it is very important to grab the audience's interest in the first few minutes while they are actually listening. If you spend 20 minutes describing the problem and background, large chunks of your audience, especially those in the relevant field, will quickly lose interest.
Fresh PhD students tend to come with the "school" mindset when it comes to presenting. Your audience is no longer your instructors who have to listen through your talk to give feedback and also to grade. You need to grab their attention and convince your talk is worth listening early in your talk. Even in such a setting (e.g., defense), it is better not to bore your audience by dumping background material.
Another way to motivate why you want to give punch-line talks is that it trains you to synthesize and to have broader perspectives. Both of these skills are essential to become a good researcher.
It is true that you can give a decent talk without following the punch-line method. It is up to you if you choose to adopt the punch-line method in the end. However, if you are unable to give one, it is a sign that you are lacking key abilities in research, and giving punch-line talks can be a good way to train them. Even if a talk does not closely follow the punch-line method, you should find most excellent talks to share many elements in common with punch-line talks.
One way of making an effective punch-line talk is to split the talk into two. One short version, followed by another talk going into more detail. The short version describes the problem, the key ideas behind your work, and what will be covered in the rest of the talk.
Towards the end of the short version, you would want a slide that summarizes your contributions, which becomes your punch line slide. The goal is to make your audience interested into what you are going to say in the rest of the talk.
The common argument I hear when I introduce the punch line method is that you need at least 10+ minutes to formulate the problem that they are solving. I claim that this is never true.
I believe that the ability to describe your work succinctly is one of the key skills that you learn through PhD (i.e., synthesis). You always have to be accurate, but precision is something that you can tweak to your audience. It is important to give a simplified view of what you are talking about, rather than being precise on things only noticed by experts in your specialization.
What you give away as your punch-line is the key idea and/or insight. The result you obtain by your approach is secondary, although it can be in the punch-line slide. This point is sometimes overlooked.
For example, achieving X speedup for benchmark suite Y on its own is not interesting. What is more important is why you were able to achieve such a result. Remember that experiments are usually there to validate and support your claims. The key research contribution should be different.
I will use a few of my past talks to give an idea of the punch-line method. Note that even my most recent slides have ample room to improve in many aspects.
This is probably one of the best set of slides that I have made, although I have too much text on many of the slides. The "Short Version" is up till slide 5:
Another thing that I am happy about this talk is the fact that there is absolutely no equations in the talk, aside from E=PT. The paper is about analytical modeling of power with 20+ equations. However, you should and you can avoid equations during talks.
This is my very first conference talk, and has many problems. It is painful to look at it now, but some efforts to give a punch-line talk can be seen. The first two slides (up to slide number 4) is very good. But then I finish the introduction without giving out why machine learning worked for tile sizes. If I were to give a talk about this paper now, I would add one or two slides to give the key insights, which I give in the later part of the talk even in the old one, to complete the short version. Specifically, the key insights of this paper are:
I hope I was able to convince you to try the punch-line method. I immediately bought this method the moment I heard about it. I really don't find any reason why the "classical" style, where you first present background, formulate the problem, describe the approach, and then show results, can be better. It may take more time to prepare your talk until you get used to it, but I strongly believe in the effectiveness of punch-line talks.