Sunday, November 01, 2015

Cake > Pie

The other day I saw something on the internet that was wrong and I had to fix it. The intent is to show that some parts of the cost structure are fixed but some are not.  This was in response to complaints that all of the revenue was going to out-of-state companies.  (Two of the slices are, in fact, handled by out-of-state companies but those companies both have their operations established locally and are employing local in-state employees to run them.)


But it also tried to show that as the toll rises, that means more money going back to the fund that's set aside for further improvements to the area being tolled.

Anyhow, why should you care?  You might not (but thanks for reading down this far), or you might take away from this that if you're trying to use a chart to get your point across, be careful to choose the chart that best tells your story.

The pie chart on the left is 42.86% of the size of the pie chart on the right, but they're presented as equals, meaning that 20 cents on the left looks much larger than 20 cents on the right.

Cakes may make a better comparison in this case:


Most of the layers stay the same.  But as the rate goes up, more goes back into future improvements. Sort of.  The fact that they lump "Enforcement, Transponders and Future Improvements" into a single category is a bit troubling but maybe they'll address that in a future post.

I know, I know.
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