I recently attended OSDI 2010 where I sat through about 30 presentations on systems-related topics. I was surprised that there were so many occurrences of things that I think should be avoided when giving a presentation.
In this post, I’m going to outline several things that, in my opinion, you should avoid when giving a talk at a conference. Keep in mind that this is just my opinion and you’re welcome to disagree, but I think you’re wrong and I’ll explain why.
Note that the examples below are all taken from the OSDI slides that were posted after the conference. If you’re an author of one of these presentations, please don’t take it as criticism of your work or you. The criticism is only aimed at your stylistic choices when creating your presentation.
This is probably the worst decision you can make. Now it’s definitely true that dark backgrounds can look nice. In fact, they can look particularly good on the screen where you created the presentation, which is why I think it’s an attractive choice for a lot of people.
The problem with this is two-fold. First, a more minor reason, is that it’s difficult to keep things consistent when using a dark background. Often you include things like images, tables, diagrams, and graphs. Many of these will have white backgrounds, so to get them to fit with your presentation, it’s extra work that you have to do.
Second, the major reason not to use a dark background is that it makes your slides much harder to read when displayed on a projector. The way that the human eye perceives blackness is relative to what’s around it. When you project black text on a white background, the black color of the text looks very black because of the large, bright, patch of white around it. When you project white text on a black background, the background looks washed out because there isn’t much light around it. This effect is also amplified because projectors can’t actually display a real black color. Black is the absence of light, so a projector simply doesn’t project any light at the pixels that are supposed to be black. Since conferences are always in brightly lit rooms, the black background ends up looking like a pale gray.
This presentation uses the Chalkboard font. It turns what should be a technical diagram into what looks like a 4-year-old’s drawing. It’s very distracting. Comic Sans also made an appearance at OSDI. Please use reasonable fonts. You can also see the poor choice of a dark background here as well.
I’ll admit that outline slides can have their place. For example, if you’re giving an hour-long talk, it can be nice to give an overview to your audience to tell them what you’re going to cover. When you only have 22 minutes, however, wasting time telling us what you’re going to talk about instead of just talking about it is silly. In this particular talk, they went back to the outline slide each time they switched sections. Even if it only takes a few seconds each time, you probably wasted a full minute just telling me what you were going to talk about. Especially when you’re throwing darts at your bullet points. No clue what they were thinking.
This is not a deal breaker, but I still advise against it. Underlined text usually looks pretty ugly, as it does here. Avoid it.
Header/Footer on Every Slide
Sometimes these can be tastefully done, but many people abuse it. In the first example, the presentation had a giant bar that says “Facebook” on every single slide. Perhaps it’s company policy; I don’t know, but it looks obnoxious and I don’t need to be reminded every single slide that this presentation is from Facebook. In the second example, it even includes the name of the conference in the footer. I often forget which conference I’m at in the middle of a talk, so I’m glad it was there. But really, you don’t need a header and/or footer on every slide. It’s distracting and unnecessary.
Walls of Text
I think people are wising up to this, but there were still a few cases. If you put too much text on a slide, then one of two things will happen: either people only pay attention to what you say – making the slide ineffective, or they spend time reading the slide instead of listening to you. Instead, use the text on your slide to support and enhance what you’re saying. The first example here just has too much text. The second example has a lot of code. Both make it difficult to simultaneously listen to the speaker and read the slides.
Again, this was just my opinion, but if you can avoid these things, please do. It will enhance your presentation and make it so people don’t get distracted.