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.
The chart, attributed to Thetica Systems, was used to accompany an article by Pro-Publica exposing the fact that, in their words,
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.
CDO Self-Dealing by investment banks (2005-2007)
If this post has given you a taste for de-junking charts, you should also visit the Junk Charts blog for much, much more.
Possibly Related Posts (automatically generated):
- Problem Pies (12 May 2012)
- Deceptive Charts #2 (20 November 2009)
- Junk Charts: Secondary Axes (6 October 2009)
- Pyramid Perversion – More Junk Charts (12 March 2010)
If the orientation of the Pro-Publica chart is rotated 90 degrees it resembles very closely the curtains in my bedroom during the 1970’s.
I understand the divisions of a pie chart have radial borders, as when cutting a pie.
Nevertheless I agree the creators of bubble charts should always be regarded with suspicion.
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