In Whacky Graphics at USAspending.gov, Seth Grimes of Intelligent Enterprise (another Seth G) deconstructs a pie chart showing Federal Spending FY 2009 on USAspending.gov’s interactive dashboard. As Seth says, this is “one downright whacky graphic. I can’t recall the last time I saw a graphic that so distorted the numbers, so I tried to recreate it (and failed).”
So what’s wrong with the chart?
Seth says, “Now I’m not a big believer in 3-D charting that simply adds depths, supposedly creating visual appeal, to a 2-D chart.” As you all know, neither are we here at Chart Busters, Inc. And of course, adding 3D effects to a pie chart is adding insult to injury.
There’s an interesting negative value, Loans, in the table below the chart. It may or may not have been added to this chart, but since it comprises less than 0.01% of the total, it isn’t visible, and they mercifully did not label it. We have seen in Pie for Dessert Again? that Excel allows negative numbers in pie charts, and merely plots their absolute values. Makes perfect sense.
Seth also asks us to ignore the labels for a moment, and judge which area is largest: the purple wedge in the front right of this ugly ovoid, the brick red wedge at the left. or the combined orange and blue wedge in the top right? To my untrained eye, they look about the same. But the labels show that these areas represent 38%, 47% and, 14% of the total. As Seth points out, this is not just caused by the magical distortion of 3D rendering, but also because the numbers don’t agree with the graphics.
We’ve also seen in Pie Chart Plotting Deficiency that even Microsoft doesn’t always care that numbers in pie charts add up. But the Microsoft chart merely left off the “Other” category, while the USAspending chart is just way off.
Seth made a 2D chart to show a more accurate depiction of the data. Note that he included the Loans wedge, but it’s not even as thick as the leader line attached to the data label.
Then Seth tries to reproduce the 3D appearance of the original chart, and he almost succeeds, except that his numbers are still faithful to the inputs.
Seth has demonstrated without doubt that the original pie was doctored. He suspects that at some point after the chart was constructed, the site design was turned over to a graphic artist who “improved” the display. Seth hasn’t demonstrated that 2D or 3D pies are a good way to illustrate this information. Okay, chart busters, what’s the best way to show this kind of data?
A boring. old. bar. chart.
I’ve made two versions, one with the minuscule Loans category:
and one without:
Seth’s planning a review of the USAspending.gov dashboard. I’m looking forward to that. I spent a few minutes on the dashboard, and found it awkward, with labels scrolling out of view before you could read them.