Shades of grey

by Stubborn Mule on 23 October 2010 · 3 comments

The recent post on the risks of smoking looked at Rifkin and Bouwer’s “Risk Characterization Theatre” (RCT), a graphical device for communicating risks. The graphic in that post, which compared mortality rates of smokers and non-smokers taken from the pioneering British doctors smoking study, highlighted both the strengths and weaknesses of RCTs.

The charts certainly illustrate the risks of smoking in a striking way and seem to elicit a far stronger reaction than drier statistical tables or charts. I also suspect that, for many people, the charts succeed in conveying the relative risks more effectively than more traditional approaches. On the other hand, there is no doubt that RCTs are extremely inefficient. The smoking graphic required an awful lot of ink to represent a mere eight data points.

In the comments on the original post, it was suggested that a colour-coding scheme could be used to combine the charts for the different age ranges, reducing the inefficiency while still preserving the immediacy of the theatre graphic. I took that as a challenge, and here is the result. Returning to the Rifkin and Bouwer theatre floor plan, rather than the more prosaic squares, I have coded deaths in different age ranges with shades of grey: the earlier the death, the darker the grey.

RCT (Shaded theatres)

Mortality of doctors born between 1900 and 1930

The risks of smoking still come through clearly in this version of the chart, but the increased efficiency may come at the expense of a potential for confusion.

What do you think?

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{ 2 comments… read them below or add one }

1 Marco aka Cracticus October 24, 2010 at 9:08 pm

Hey, Stubborn

As I am a smoker (believe it or not), this kind of subject tends to make me feel uncomfortable… So I think I need a smoke! ;)

Seriously, I don’t think this kind of new device is such a good idea.

Let’s put it this way: if people, even doctors, have difficulty understanding even the simplest charts, the introduction of newer types of charts will likely make the problem worse, not better.

The best thing would be to train people so they at least are able to understand the simplest charts and tables (which people don’t understand, either).

By the way, I am thinking about writing to the ABS. They have a blog where one can comment on their work and make suggestions:

http://blog.abs.gov.au/Blog/mapblog2010.nsf/

2 Stubborn Mule October 25, 2010 at 9:17 am

@Marco: I take your point about the dangers of introducing new charts. Indeed my own attitude to the RCTs is cautious. I think that, used with care in certain circumstances, they can be useful but only because they draw on ideas people are already familiar with (i.e. the floor plan…even the idea of occupied seats should be accessible). For the same reason, I don’t think that the shaded version really works–it pushes the idea too far and beyond the point at which it’s intuitive.

Thanks for the pointer to the ABS blog. I didn’t know about it.

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