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Re: st: RE: The not so humble pie
When we used to prepare data summaries to go to the Texas legislature,
we used to refer to them (internally) as "Bubba graphs." For
displaying data simple enough to be understood by a legislator, pie
charts worked fine. Precision was not the goal. We did not ask
anyone to compare across pie charts.
Dave
====================================
David C. Bell
Professor of Sociology
Indiana University Purdue University Indianapolis (IUPUI)
(317) 278-1336
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On Oct 21, 2009, at 12:44 PM, Nick Cox wrote:
Thanks for the thanks.
Being rude about pie charts is all good fun and, for many of us, an
acceptable variant on blood sports. But if precise decoding of
proportions is the aim, then tables beat pie and bar charts hand
down, or the actual numbers can just be added to the graph!
One major objection to pie charts is that their effectiveness breaks
down very rapidly as displays depart only slightly from extreme
simplicity. You need only think about comparing 30 category
proportions across 3 pie charts, or 10 categories across 10 pie
charts, to realise that.
Irrelevantly, but it just sprang to mind: Some of you may enjoy this
algorithm, probably known throughout history, for sharing a pie
(cake, whatever) between two children. One child gets to cut and the
other gets to choose.
Nick
[email protected]
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