Design guru Edward Tufte famously lambasted pie charts in The Visual Display of Quantitative Information and went on to say
the only worse design than a pie chart is several of them
While pie charts do have their defenders, the basis for the contempt in which pie charts are held by Tufte and others is that the human eye is far better at differentiating position and length than angle and area.
So, I was a little disappointed when a correspondent drew my attention to this rather bubbly chart which appeared on an article by the excellent team at Pro-Publica (click on the chart to see a larger version).
Pro-Publica is an independent, not-for-profit newsroom that specialises in investigative journalism. They have collaborated with the team at Planet Money (one of my favourite podcasts), and have perhaps delved deeper than any other journalists into the arcane world of CDOs, a topic I have touched on a few times here on the Stubborn Mule.
Over the last two years of the housing bubble, Wall Street bankers perpetrated one of the greatest episodes of self-dealing in financial history.
It is a fascinating story, but it would seem that Thetica’s graphics department was carried away with a visual pun on the title of Pro-Publica’s post “Circular CDOs” when they chose to use circles to depict the growth in CDO recycling from 2005 to 2007. It might look pretty, but the circles make it much harder to discern the trend and to compare the four banks. Pro-Publica’s article deserves better.
In the tradition of my junk chart posts, I have produced an alternative visualization of the same data. I am sure that graphic designers could improve on the colour-scheme, but this simple lattice of line charts makes for a much clearer view of the data.
If this post has given you a taste for de-junking charts, you should also visit the Junk Charts blog for much, much more.