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> Date: Thu, 19 Mar 2009 11:31:44 +0000 > From: "Moore, Robert" <[log in to unmask]> > > I don't think I've used pie charts, except perhaps when showing how > wealth is divided, where 'slices of the pie' make some sort of sense. But > I get the feeling from some of the exchanges (Jane Galbraith for example) > that pie charts are not much loved by statisticians. Is there a technical > reason for this? Pie charts are not very popular with statisticians because it is difficult to make precise comparisons of angles, especially when they are displayed in different orientations as they must be in a pie chart. Think about how easy it is to detect even tiny differences in bars when they are displayed side by side -- one of them sticks up more than the other. No such ease of comparison in a pie. It is much worse with the common "tilted pie" (drawn as an oval to make it look like a pie tilted in space, perhaps about to hit the viewer in the face). In that display, the same sized segment has completely different shapes depending on its orientation! In general the statisticians who write about visual display dislike "3-D" plots since they require the reader to first translate the 2-D rendering on a flat surface into a visualized 3-D object and then manipulate the elements in 3-D space to make comparisons. Beware the Ides of March -- and Excel! ****************************************************** Please note that if you press the 'Reply' button your message will go only to the sender of this message. If you want to reply to the whole list, use your mailer's 'Reply-to-All' button to send your message automatically to [log in to unmask] Disclaimer: The messages sent to this list are the views of the sender and cannot be assumed to be representative of the range of views held by subscribers to the Radical Statistics Group. To find out more about Radical Statistics and its aims and activities and read current and past issues of our newsletter you are invited to visit our web site www.radstats.org.uk. *******************************************************