Pie Charts ​

New Video: The Science of Pie Charts ​

The common explanation for how pie charts work is that we read them by angle. That of course would mean that donut charts would be bad, because you can't see the angle when you take away the center of the pie. Changing the radius of a slice wouldn't matter though, because that doesn't change the angle. But there is no evidence that angle is how we read pie charts, quite the opposite actually. In this new video, I walk through five reasons why angle is not how we read pies, and what that means for other things we like to assume about them. Read more…

eagereyesTV Episode 3: 3D Pie Charts For Science! ​

How do we read pie charts? This seems like a straightforward question to answer, but it turns out that most of what you’ve probably heard is wrong. We don’t actually know whether we use angle, area, or arc length. In a short paper at the VIS conference this week I’m presenting a study I ran to answer this question – a study using 3D pie charts! Read more…

A Reanalysis of A Study About (Square) Pie Charts from 2009 ​

After my recent posting on the results of our pie charts studies, Jorge Camoes teased me on Twitter about square pie charts. So I dug up the data from a study we ran many years ago to look at how well they compare to bars, pies, and squares. Read more…

Ye Olde Pie Chart Debate ​

You may think that the debate over pie charts was a new one, but it has raged on for at least 100 years. Brinton started it in 1914, and great drama unfolded in the pages of the Journal of the American Statistical Association in the 1920s. Read more…

In Defense of Pie Charts ​

Pie charts don't get much respect. They're almost always considered the wrong choice by those supposedly in the know. But how do we know that this is true? What evidence do we have to support this? The truth is, not much. And when we start digging for proof, it turns out that pie charts are much better than we want to admit. Read more…

Understanding Pie Charts ​

Pie charts are perhaps the most ubiquitous chart type; they can be found in newspapers, business reports, and many other places. But few people actually understand the function of the pie chart and how to use it properly. In addition to issues stemming from using too many categories, the biggest problem is getting the basic premise: that the pie slices sum up to a meaningful whole. Read more…