This blog entry was written by Bryan Pierce of Perceptual Edge.
Last week Stephen published an article entitled, “Our Irresistible Fascination with All Things Circular,” which describes how people’s seemingly innate love for circles has led to the creation of many dysfunctional graphs, such as pie charts. Today, another example of a poorly designed circular graph came to our attention. A couple months ago, Sunlight Labs hosted a contest called “Design for America,” which asked designers to create displays of government information for the purpose of making “government data more accessible and comprehensible to the American public.” A couple days ago, they announced the winners. In the data visualization category there are plenty of examples of what not to do, the worst of which appears below.
This display is supposed to be used to compare the 2009 US Federal Contract Spending for several sectors to the amount of Media Coverage that those sectors received during the year. As you can see, the designers seem to have fallen into the same sort of circle-lust that Stephen wrote about last week. In this case, the circular shape seems to be entirely arbitrary, because the quantitative data is encoded only by the thickness of the rings. These circles serve the same purpose as stacked-bar graphs; they’ve just been stretched out and distorted into a circular shape.
Ignoring the uselessness of the circular design for a moment, what does this visualization tell us? The only thing it tells me is that Defense spending was vastly under-reported in the media during 2009 while Health and Energy spending were comparatively over-reported. Without a lot of effort, I can’t make meaningful comparisons between the information in the other sectors, because they’re too small and hard to see, and I can’t even make comparisons between the three largest sectors with much accuracy. It’s also difficult to read the names of the smaller sectors because they overlap.
Although it might not be as sexy, two horizontal bar graphs next to one another would work better: one for Federal Contract Spending and one for Media Coverage. The Federal Contract Spending graph could be sorted from highest to lowest and the Media Coverage graph could present the bars in the same order. This would make it very easy to compare a sector’s spending and media coverage (because they’d be aligned in a row), it would make exceptions jump out (because there’d be a difference in the length of the bar in the Media Coverage graph compared to its neighboring bars), and it would be easy to read the names of all the sectors. It would still be hard to decode the contract spending in some of the smaller sectors accurately (because their bars would be so much smaller than the Dept. of Defense bar), but at least all of the bars would share a labeled quantitative scale, which would make the task easier.
Another useful alternative, which would put even more focus onto the relationship between Federal Contract Spending and Media Coverage, while making the exceptions jump out, would be a scatterplot that displayed Federal Contract Spending on the x-axis and Media Coverage on the y-axis.
It is unfortunate that most of the winners of Design for America contest don’t represent useful designs. The fact that the circular graph above was a winner either means that the judges of the contest had a terrible selection of designs to choose from, or that the judges don’t understand data visualization. This is sad, not just because people are being given $5,000 prizes for impoverished displays, but because this information is important and it could benefit people if it was presented in a useful way.