Get real about what you can achieve in a slide presentation

What will the typical audience member remember about your presentation 24 hours after hearing it? Most audience members don't take notes, and even for those who do, the slides are usually going by too fast for detailed note taking. So the answer is NOT MUCH.

As a presenter you can take pride if the audience can remember a few key points AND MOST IMPORTANTLY, if your presentation motivates them to learn more. If it inspires them to read your journal article, send you a follow-up question by email, or corner you after your talk, then you have succeeded. This is not to say that individual data slides are unimportant. It may be that a particular piece of data motivates an audience member to learn more. It is the individual data slides that reinforce the few key points that the audience might retain.

A slide presentation is a poor way to reliably transmit data and findings. It is a very effective way to make a scientific argument, motivate people to scrutinize your data at a later point, challenge you, and consider the implications of your work for subjects of interest to them. So build you presentation around a small number of thematic points you want the audience to retain (see earlier "Tips" on writing an essay before doing slides). Don't make your presentation a "data dump." Resist the childlike urge to tell the audience everything you know and have done. LESS CAN BE MORE!

There are six things wrong with this slide

Here is another typical biomedical research slide. There is way too much information and a lot of abbreviations known only to the speaker. So let's analyze the problems in this slide.

The following numbers correspond to the slide pictured below.

1. The label for the vertical axis is unreadable. The audience will be twisting their necks to read and it is a long involved label. All labels should be displayed horizontally. Just because Excel pops out vertical axis labels doesn't mean you have to use them. Cover the area with a solid white block and then rewrite the horizontal axis, hopefully with simpler words. Remember, your spoken words can supplement a shortened title.

2. What are S and AS? Even if some in the audience know what these abbreviations are, you don't want them spending 20 seconds trying to remember and not listening to you (sense and anti-sense).

3. The horizontal axis could use a clean text label.

4. There is too much data on this slide. Pick one or two of the bar graphs and explain them. If you need to show all the data on this slide then you will need multiple slides.

5. Once you know which subsets of the above data you plan to show then you can create a simple title that conveys the point you want to make

6. The bar graphs are simply quantification of the blot data shown on the right. You don't need both. Remember a presentation is not a journal article, you can't prove everything in a presentation. You want to inspire the audience to read your journal article and examine your methods. They can see the raw data in the journal article. If you absolutely need to show both data sets then show the blot data on a separate slide.

Never show a slide like this!

This slide below is typical of what we see in biomedical research presentations. Too much data and nothing to help the audience focus on the essential message.

What happens when a slide like this appears on the screen? The audience spends 30 seconds staring at the figure trying to focus in on the essential point and doesn't listen to the speaker. After some time the audience gives up and turns their attention to the speaker, who probably isn't explaining the slide anyway because there is way too much data on it. The visual and oral narratives work against each other, destroying any rationale for a slide presentation.

Why would anyone show this kind of slide? I have heard several explanations: 1) the speaker is comforted by having all the data in front of them, 2) it's easy to do because it is lifted from a journal article, or 3) it's not necessary to think through the oral presentation of this slide because it's a pretty useless slide. All of these answers involve helping the speaker. However a presentation is about helping the audience!

Before showing this kind of slide the presenter needs to ask him/herself the message he/she is trying to convey. Perhaps it is the growth in industry screen failures shown in the bottom of the 3 tables. Perhaps it is a comparison of this with another trend. Whatever it is, the slide should be designed around this message. One overarching message for each slide! The only message of the slide below is, "I gathered a lot of data." If that is your message, then tell the audience they don't need to read the details and move onto the next slide quickly.