I recently attended a one-day course by Edward Tufte in Boston and was subsequently inspired to think about the ways in which we go about creating more effective visuals. With things like graphs and charts comes a temptation to overcomplicate things by adding what Tufte calls ‘chartjunk’. So to help you avoid chartjunk in presentations you might be creating, so you can instead create an effective and engaging graphic, here are 3 important lessons from Tufte’s teachings.

For those who are unfamiliar, Edward Tufte is a Professor Emeritus of Political Science Statistics and Computer Science at Yale University and a pioneer in the field of data visualization. He has written four books on visual reasoning and data, Beautiful Evidence, Visual Explanations, Envisioning Information and The Visual Display of Quantitative Information. In Tufte’s words, “The information is the method…” meaning that data on slides should speak for itself without interference from things like chartjunk, a term he coined to describe the cluttered mess of information one usually sees crammed into graphs. In his one-day course, Tufte went through specific examples in his books and supplemented them with examples from current popular media (such as the New York Times) to explain how the method in which we communicate data has a huge influence on how people understand it. In particular, there were three lessons he talked about that we currently apply in our presentations that can improve your methods of information transfer and leave you with a more engaged and personally invested audience. So, onto the first!

Scales of measurement

One of the first things Tufte mentions on pages 15-17 of Beautiful Evidence is the importance of clarifying scale in diagrams. In the first section of the book, titled Mapped Pictures: Images as Evidence and Explanation, he mentions how different historical texts, (including Markus Bloch’s Ichthyologie, which contains illustrations of 216 different fish) fail to designate a scale for their subject matter, and in turn make it impossible for the reader to interpret a crucial piece of information. He notes how by simply including a reference for scale such as a “universal ruler”, one could dramatically improve the information transfer of the pieces.

avoid chartjunk in presentations

This concept is easily applicable to PowerPoint as well. When you’re talking about products for example, scale holds significant explanatory weight for the audience and seeing a product fully in context is incredibly valuable for sales. If you’d like to include imagery of products in your next presentation, make sure to show products in the end user environment instead of showing them floating in space on a white background. This will allow your imagery to be more accurate and effective, and people will gain a much better understanding of how the products would actually be used and more likely to become customers.

Labels

Another way to avoid chartjunk in presentations that you can take away from Beautiful Evidence is the importance of labeling imagery or data in a way that aids understanding (pg. 42-45). Specifically, Tufte believes that having a separate key with a graph to explain things (like what a certain symbol, color or shape means) takes away from understanding and creates clutter. He goes on to explain that having information set up this way causes confusion and failure of information transfer because the audience has to keep looking back and forth between the key and the information itself to interpret it. He shows an example of a photo of four dogs. The first has the names of the dogs labeled next to them in large print, and a second example has the name labels located in a separate key with letters on the dogs corresponding to the labels. The lesson here is that the former is more concise and easier to read for anyone, while the latter adds ‘chartjunk’. This is because the change in location of the labels does not contribute positively to their effectiveness, and instead it overcomplicates a concept that should be very straightforward (i.e names of dogs).

avoid chartjunk in presentations

This kind of idea is also important when you’re making a presentation. If possible, you should try to eliminate keys and instead try to label imagery on the image or next to the image itself. This will help people who are trying to interpret your data quickly pinpoint what’s what and they won’t get tired of trying to “translate” your data and give up all together. This will lead to a better experience for everyone involved and allows the data to speak for itself, which is one of the leading themes from Tufte’s work.

Replacing text labels with images

A final lesson, that is an extension of the last, is that sometimes text labels would be more effective as images instead. On page 118-121 of Beautiful Evidence, Tufte gives an example of a graph that originally uses text labels for different animals to illustrate their position on a brain mass vs. body mass chart. He then replaces the text labels with actual imagery of the different species, and almost immediately the chart is easier to grasp. Without the words we can group animals visually, for example we can notice patterns like the cluster of dinosaurs to the right or the group of ape-like creatures to the left. Being able to pick out these patterns is extremely valuable, because it means people can build associations with the visuals, which increases understanding and helps with retention. On PowerPoint, using imagery in this way would probably require ditching the live graphs and instead recreating your graphs with PowerPoint shapes. We cover how to do this in our Advanced PowerPoint Training.

avoid chartjunk in presentations

However, the easiest way to get started applying this method would be just to ask yourself whether the content you’re showing could be represented visually, and if so, make the switch from text to imagery.


I agree with Tufte that data in itself is compelling, for example using graphs in a presentation can be a great tool. However, as a tool they need to be presented correctly in a compelling way. To avoid chartjunk in presentations all the content on your slide should be as concise and effective as possible, and in many cases this involves building context, getting rid of text labels, and adding more visuals. If you’re interested in learning more from Tufte in regards to data visualization, I would highly recommend picking up a copy of Beautiful Evidence and his other publications on the subject, as they are definitely a great resource for anyone interested. By applying even a few of his teachings to your next presentation you can be sure that people will understand your data better and also be more interested in it, and you’ll get much better results with future presentations.

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Amy Post

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  1. Image of Dean Kovack Dean Kovack says:

    Id like to know more about this ! ty DK

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It is, quite simply, the best deck we have. I did a nice presentation with it yesterday and would like to do the same next week... I am sure it will get a lot of use. The visual impact and flow are compelling!

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