Melissa Marshall is a faculty member at Penn State University in the Department of Communication Arts & Sciences where she teaches scientific presentation skills to engineering students. She is a crusader against bullet points and an evangelist for effective slide design. Along with her colleague Michael Alley, Melissa provides guest lectures and workshops on the Assertion-Evidence slide design all over the world. You can learn more about Melissa here.
In this conversation, Melissa discusses how you can effectively design scientific slides.
Geetesh: Tell us about the presentation slides you are involved with as part of your work, and are medical and engineering slides really different than other conventional slides?
Melissa: Because of the level of technical content in most science and engineering presentations, it is critical to have presentation slides that help an audience to understand, remember, and appreciate the importance of the work being presented. Unfortunately, the typical, commonly used design of PowerPoint slides is primarily text-based with a phrase title supported by a bulleted list. As presenters, we can do better!
When a speaker uses text heavy slides, this can lead to cognitive overload of the audience (otherwise known as Death by PowerPoint). There is a limit to how much words-based information your audience can process. Whether words are spoken or written on a slide, it is verbal information that is processed in the same part of the brain. And since a talk itself is composed of spoken words, when a presenter has slides that are also primarily text, this causes the audience to be overwhelmed with verbal information, so they will often only read the slides or only listen to the presenter which is evidence of cognitive overload. Additionally, bullets do not show connections or relationships of the content being presented. As a result, it is very difficult for the audience to determine the most important information on the slide. This issue is magnified in a technical presentation that contains challenging content that an audience has to work hard to understand. Due to the challenges of communicating about technical ideas, it is essential that scientists and engineers design their slides to make their content most easily understood by their audience.
The Assertion-Evidence slide design utilizes several important principles of how people learn to allow presenters to create slides that help an audience to understand and remember the content. The Assertion-Evidence slide design is characterized by a concise, full-sentence assertion at the top of the slide that communicates the main message of the slide. This assertion is then supported on the body of the slide by visual evidence, instead of a bullet list. Visual evidence can be photos, drawings, diagrams, graphs, films, or equations.
The short, full sentence assertion leads to more clarity and focus in a presentation. When a presenter carefully considers the key message of each slide and communicates that message in a full sentence, this causes the speaker to emphasize the most important details of the work being presented. Most presenters put a phrase at the top of a slide like “Results”. Unfortunately, this does not provide much of a filter, so presenters will often then crowd the slide with too many details that are related to “Results”. Instead, if the presenter states at the top of the slide what the audience should know about “Results”, they might write on assertion like “A higher weight percentage of Nickel results in higher resistance to corrosion.” This causes the slide to be more focused and allows the audience to very quickly hone in on the most important take away. And, if the audience gets a bit confused, a well-crafted assertion will provide a life line that will get them back on the path of the talk.
The second key step is to support the assertion with visual evidence. This is the most powerful feature of this strategy. It should be the goal of a presenter to use their slides to do something for them that the words they are saying cannot. That means that presenters need to maximize the visual components of their slides and limit the use of words. Visual information is processed in a different part of the brain, and is often much more memorable to an audience. And, as human beings, we know this to be true as illustrated by the common saying “A picture is worth a thousand words.”
It is important that the visual evidence presented is a relevant, quality visual—clip art will not suffice. Excellent options include: photos, drawings, diagrams, graphs, films, tables or equations. Speakers should not be afraid to use the tools of PowerPoint to draw their own visuals, if they are not able to find something that already exists to show their concept. If you can picture it in your head, you can often make it yourself–and you don’t need to be a computer wizard to do so. When the body of your slide is primarily visual, you as a speaker become a “tour guide” for the slide. You point out what the audience should notice about a particular graph or image or the areas that are notable or important. The end result is that both the speaker and the audience are more engaged and connected throughout the presentation.
Here are two strong examples of Assertion-Evidence slides:
Figure 1: Slide by Kathryn Kirsch, researcher in Mechanical Engineering at Penn State University.
Figure 2: Slide by Genevieve Brown, researcher in Bioengineering at Columbia University.
Examples, templates, and further discussion of the Assertion-Evidence design can be found on the website Rethinking the Design of Presentation Slides managed by my colleague, Michael Alley, author of The Craft of Scientific Presentations and originator and developer of the research on the Assertion-Evidence slide design.
Discussion, tips, and examples for effective scientific presentations can be found on my site Effective Presentations in Science and Engineering.
Geetesh: You mention on your site that “science not communicated is science not done” – love that quote! Tell us more about your thoughts that framed this quote.
Melissa: Much of the future health, happiness, and safety of our world will depend upon the innovations of scientists and engineers. In order for a breakthrough in the lab or a creative design idea to gain support, it has to be communicated in a way that an audience outside of the lab or design firm can understand and appreciate the significance of the project or findings. Often, the decision makers who will impact whether a project will gain funding or move forward are executives, managers, government officials, or even the general public. These audiences often do not have the same technical background, so it is imperative that scientists and engineers can communicate the significance of their work in order for it to succeed. If you have an incredible result in the lab, but are unable to clearly establish the significance of that finding to a broader audience and it is ignored instead of advanced, then the work has not been successful.
In order for science to have an impact, it has to be communicated. One area where we are seeing great advancements in communication of technical ideas is through TED. TED stands for Technology, Entertainment, and Design and is committed to finding and sharing “Ideas Worth Spreading”. And they spread those ideas through short, very well-done presentations. TED is creating a platform for many important ideas in science and engineering to be communicated to the world and the speakers are really stepping up to the challenge. I encourage you to check out some of the presentations on TED and see what you can learn about your own speaking from these examples. And it is worth noting that you almost NEVER see text filled, bulleted slides from TED speakers.
Good scientific presentations take time to prepare, but they are worth it. The research matters and deserves to be presented in a way that will allow an audience to see its significance. Critical thought into slide design is a great first step.