Andrew Gelman is giving a talk later today at MIT on graphics and infoviz. You can read about it in his blog here, including links to his slides and paper. It makes for a nice overview of the situation, the problems and the possibilities. I think he is onto something with the “graphic as puzzle” idea. That does seem a feature of the successful ones, along with telling a story, catching your eye, provoking an emotional response and revealing something which would be really hard to do in words or tables.
The example above is from a study from the University of Saskatchewan* that showed that including “chart junk” is not necessarily a barrier to understanding or recall – although as Gelman points out, their chart junk is really good junk. I like the subtle touch – it is only the 8% that ends up on the woman’s lips – which tells the underlying story. Anyone who objects to the curvy outline in the pie chart is a tedious pedant; have you ever seen anyone look at a pie chart and then ask “now, where’s my protractor?”
* – I guess the impetus to study eye-catching shapes comes from the province itself. Like the T-shirts say: