A shark attack on a chart

Happy New Year!

Starting 2011 with shark attacks courtesy of Julien D.

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It seems like the good chart did not survive a shark attack if one were to judge from what's left of it.

It's a distorted pie chart with some kind of 3D hemispherical add-on, or it's a cross-sectional chart with the top of a sphere lopped off.

Charts of the USA Today variety do not usually feature here but this one has the aspiration to inform readers -- the chart appears on a web page that purports to correct some myths about shark attacks.

The biggest casualty of the shark attack is the ordering of the data labels. It is a brain teaser as to what criterion was used to order the pie slices: it's not the total number of accidents, nor the number of deaths, nor the death rate, nor alphabetical.

It's also unclear why the data labels were made vertical. The palette of colors is, however, typical of pie charts.

Since a death rate is usually defined as deaths / total accidents, not the other way round, even the numerical data labels is harder to read than necessary.

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There are two primary questions this chart is intended to address: the prevalence of different types of shark attacks, and the death rate of each type of attack (as a proportion of reported accidents).

We try a scatter plot showing these two metrics, adding notes to point out where the interesting data is.

 

 

Comments

[Jon Peltier]

The scatter chart is far superior.

What was plotted in the pie?
What is the time frame of the chart's data (the cited web page didn't say)?

[Mike]

Colors suck for us color blind folks. Let me tell you.

[Rick Wicklin]

It is also interesting that the Shark Foundation data differ from the statistics at the International Shark Attack File: http://www.flmnh.ufl.edu/fish/sharks/statistics/species2.htm
Still, I suppose we can forgive some discrepancies. As the ISAF web page notes, "positive identification of attacking sharks is very difficult since victims rarely make adequate observations of the attacker." Yeah, I can believe that!

[Rick Wicklin]

Although sometimes a stacked bar chart can be misleading, I think it works for these data. An alternative presentation is at http://blogs.sas.com/iml/index.php?/archives/72-When-Sharks-Attack!.html

[elly]

Thanks, this helped I guess....