In the first months of Poll Everywhere’s life, we used to have a pie chart mode that people could select as a way to present their poll results. Our usage reports showed that nobody was using pie charts. When we took them away, nobody complained. And nobody has requested pie charts since!

Pie charts have been on our mind lately. We’ve seen a few around.

Everyone who has an interest in the effective communication of information knows the work of Edward Tufte. I’ll never forget the first time I saw his 32 page essay that compares PowerPoint to Communist Russia on the cover, and his analysis of the slide that failed to communicate the risk of O-ring failure in the 1986 space shuttle Challenger disaster.

Tufte has a clear opinion on pie charts. In the second edition of The Visual Display of Quantitative Information, Tufte says on page 178, “Given their low data-density and failure to order numbers along a visual dimension, pie charts should never be used.”

We generally agree. Picture real-time voting in a large audience. Imagine that three of the voting options are in a tight race for first place with 26%, 23%, and 25% respectively. A bar chart reveals the leader at a glance, without forcing the eye to search for a backup data source such as textual data labels. Especially when data is changing, a pie chart doesn’t tell the story without requiring lots of iterative eye movements.

Interestingly, Tufte also has a criticism for bars as well: the length of a filled and labeled bar is redundantly shown in six ways (2 sides, cap, fill, label data, label position). Fortunately, most of our polls have the space to spare, and audiences prefer this kind of linear reinforcement. As viewing distance increases, the redundancy of bar graph visual information converges gracefully.

One thing we hope to release soon is the ability to pick from predefined visual themes: preselected combinations of colors, graphic effects, data positions, and background overlays. Maybe we’ll try creating a Tufte theme.

But to get past the religious debate of chart minutiae, you’re the customer and we love listening.