Someone tweeted a link to a bad pie chart. I forget who it was: if it was you, let me know in the comments and I’ll give you credit here. But it’s not merely a bad pie chart, it’s an awful pie chart. A wonderful, awful pie chart.
And the Grinch got a wonderful, awful idea.
The chart appeared in 2011: The Year in Review on the Kickstarter web site. Kickstarter is a unique program for funding projects, which lines up proposals with backers who pledge support for them. It actually seems like a great program, but they need to work on their graphs.
The cited article describes their funding activities for last year. The pie chart contains much of this data, but not in a form that is remotely useful.
This is the first view I had of the pie chart. All of the slices are the same size, which is strange, and no information is visible except for the category names, which is awkward.
More ominous is the label above the chart that reads “Mouse over a color to see that category’s stats.” So you have to mouse over the chart to show any of the data.
I first saw this on my mobile, and, well, I couldn’t mouse over anything. Later I loaded the page on my laptop so I could examine it in greater detail. I moused over the pie, expecting to see a popup with some data. Nothing. I spent more than a minute mousing over the picture before I realized the data was displayed in the same rectangle that first directed me to mouse over the chart.
When you mouse over the wedge, you need to note the category name, and try to memorize three numbers, before you move to the next wedge and its three numbers. And the next, and, uh. . .
I’ve been calling this illustration a “chart”, but it’s not really a chart. It’s not really a graph. The best I can call it is a picture, or an illustration.
It’s not a graph, because not a single byte of data is displayed graphically in the illustration. You see the data when you mouse over a segment of the pie, then it disappears when you mouse over another segment. If you can’t remember the text, you cannot compare the values from segment to segment. Maybe I was stupid not to notice the data the first time I moused over a slice of pie, but nobody is smart enough to keep all of this text in their memory.
It’s so bad, that I moused over the picture for several minutes, and had no idea which of the categories had more or less support, and whether support measured by amount pledged tracked with number of backers or number of funded projects.
Interactivity is okay when it’s done effectively. The user should not need the mouse to see the overview of the data. The interactivity should be used to allow deeper investigation into subsets of the data and into alternative views.
A Better Chart
This is a rough draft of a different view of the data. I hardly spent any time on the labels, just enough to give viewers a taste.
It’s a simple panel chart, with three panels of bars, one each for amount pledged, number of projects, and number of backers. The categories are sorted by decreasing order of amount pledged, not alphabetically. The sorting is almost preserved in the other panels, which makes sense: more projects and more backers would gather more pledges.
Every bit of data that is hidden within the original pie is clearly displayed in the panel chart. No need to play cat and mouse to see information, no need to rely on a weak short term memory to allow comparisons and to see trends.