An excellent visualization, according to Edward Tufte, expresses "complex ideas communicated with clarity, precision and efficiency." I would add that an excellent visualization also tells a story through the graphical depiction of statistical information. As I discussed in an earlier post, visualization in its educational or confirmational role is really a dynamic form of persuasion. Few forms of communication are as persuasive as a compelling narrative. To this end, the visualization needs to tell a story to the audience. Storytelling helps the viewer gain insight from the data. (For a great example, how much do you think steroids have influenced baseball?)
So how does a visual designer tell a story with a visualization? The analysis has to find the story that the data supports. Traditional journalism does this all the time, and journalists have become very good at storytelling with visualization via infographics. In that vein, here are some journalistic strategies on telling a good story that apply to data visualizations as well.
- Find the compelling narrative. Along with giving an account of the facts and establishing the connections between them, don't be boring. You are competing for the viewer's time and attention, so make sure the narrative has a hook, momentum, or a captivating purpose. Finding the narrative structure will help you decide whether you actually have a story to tell. If you don't, then perhaps this visualization should support exploratory data analysis (EDA) rather than convey information. However, for the designer of an exploratory visualization it is still important to spark the viewers' imagination to encourage examining relationships among and facilitate interacting with the data - think gameification.
- Think about your audience. What does the audience know about the topic? Is it meant for decision makers, general interested parties, or others? The visualization needs to be framed around the level of information the audience already has, correct and incorrect:
- Novice: first exposure to the subject, but doesn't want oversimplification
- Generalist: aware of the topic, but looking for an overview understanding and major themes
- Managerial: in-depth, actionable understanding of intricacies and interrelationships with access to detail
- Expert: more exploration and discovery and less storytelling with great detail
- Executive: only has time to glean the significance and conclusions of weighted probabilities