In his book, The Visual Display of Quantitative Information, Edward Tufte coined the term, ‘chartjunk’, which refers to unnecessary graphics and information used in data visualisation. The cluttered mess of data often used to embellish charts and graphs may help the data look more technical or official, but it does little to help audiences understand and retain the information displayed.
It’s a common mistake designers and presenters fall into, embellishing data visualisation to make things look more compelling and authoritative. Sometimes this can be necessary, but often it’s simply adding more chartjunk that makes data more difficult to understand and interpret.
While data can often be a useful means for making a more compelling agument to audiences since people tend to trust figures and statistics more than facts. However, when visualising and presenting that data, there are some important things to bear in mind to ensure you avoid chartjunk by demonstrating context, eliminating unnecessary elements, and using imagery wisely.
Scale of Measurement
Tufte noted the importance of avoiding chartjunk, highlighting the value in giving audiences all the information necessary for them to quickly interpret the data. In Tufte’s book, he mentions the importance of clarifying scale in diagrams.
Tufte noted that many historical books fail to designate a scale for their subject matter, making it difficult for readers to interpret with missing information. By including a reference for scale, such as a universal ruler or simply contrasting elements, you can dramatically improve information transfer.
PowerPoint Designer is integrated with Microsoft Research Perspective Engine, which recognises when a slide contains a large number that might be difficult to interpret and puts into context by automatically augmenting the text with a corresponding perspective. For example: “Victoria is 237,629 km²” may be hard for audiences to interpret. However, adding “that’s about equal to the size of the UK” offers audiences some perspective.
Scale and context make information easier to understand and empathise with personally. When you’re trying to provide scale for an image, it’s better to use complete backgrounds to provide more realistic context. Placing your latest product against a plain background isn’t as helpful for audiences trying to understand the size and functionality, so show the product in use or in its most natural setting. This helps audiences empathise with the end user.
Tufte also advised readers to avoid chartjunk through effective labelling. He believes having a separate key adjacent to a graph or chart makes its more challenging to understand and creates clutter. Having information set up this way causes confusion and failure of information transfer since audiences are forced to look back and forth between the key and the data being interpreted.
When adding a graph or chart in your presentation, eliminate keys wherever possible and simply label the image or graph directly. This makes for an easier viewing experience and provides immediate context, ensuring audience interpretation is faster and more seamless.
Images Over Text
The final point that Tufte argues for avoiding chartjunk is how images can be more effective and accessible than text labels. Images are more universal than text, easier to understand and interpret, and visually more appealing than chunks of text. Using a visual rather than text representation helps audiences to notice patterns and trends intuitively, which helps improve understanding and memory retention.
Final Tips for Avoiding Chartjunk
As with any presentation, understanding your audience is critical in visualising data. Keep your audience in mind when deciding on images, charts, and labels. Always design with a clear understanding of what your audience knows and is seeking to know through your presentation.
Understand your content and what you’re trying to convey to your audience. Any data visualisation you use should be for the benefit of your audience and help them get greater context for the information being presented.
Be conscious of how your data and presentation will be displayed. When presenting to a live audience means your on-screen visuals will only be up for a moment, so it should be clear, easy to understand, and visually engaging.
Captions provide more information about what the figure covers. If you are creating a graph, ensure each axis is labelled and add caption to highlight crucial information.
Colour is helpful for highlighting specific data or areas, so use colour sparingly to help focus audiences’ attention on the most important data.
Data should always be presented objectively to help audiences draw their own conclusions, so conscious of how your captions, labels, and visual elements all convey an impartial position.
To avoid chartjunk, remember that not all information is vital – be selective and remember that less is always more. If you have any doubt about whether or not information should be included, chances are you can probably leave it out. If the data doesn’t help your audience understand or empathise with your content, it’s simply more chartjunk.