Visualizing Health and Healthcare Data

Chapter EightGraphs and Charts to Never Use or Use with Caution

When “Cool Displays” Are Anything But

We all aspire to create displays of exceedingly complex health and healthcare data that are elegantly simple, powerfully informative, and memorable for the stories they reveal. Nevertheless, all too often, viewers request, and some visualizers are delighted to create, complicated and seemingly “cool” charts that only make data more difficult to comprehend and remember.

One reason people love “cool” graphs and charts (for which data visualization pioneer Edward Tufte coined the term “chartjunk”) may be a function in part of biology. Humans are naturally programmed to feel a positive connection to specific shapes, such as circles, as well as new and exciting visual objects ("Look, something shiny!"). However, regardless of what may be an innate tendency, it is the job of health and healthcare and data visualization experts to steer people toward the most useful charts—those that, according to current research, communicate in an understandable, explainable, and actionable manner—rather than the most attractive ones.

Simple lack of training and awareness of why a particular chart is ineffective at communicating information may also make users susceptible to it. As covered in Chapter 4, the best practices of data visualization are not intuitive—they have been developed over time based on principles of human vision and cognition that must be studied and learned.

Those who create ...