Happy Pi Day everyone! It’s especially fun this year because today is 3/14/15.

If you’re a regular reader of this blog or of the data visualization field in general, you’re probably well aware of many people’s disdain for pie charts (see, for example, the WTFViz site or this great article by Stephen Few). But I’m not going to dig into that debate here. Instead, at the urging of Xan Gregg, I am going to join his #OneLessPie appeal.

How? Well, I’m going to let others do the work. I’m currently–literally, right now–teaching my final data visualization class at the McDonough School of Business at Georgetown University. To celebrate Pi Day, I’ve given each of my 46 students a pie chart and asked them to recreate it using data visualization best practices. Here is the assignment:

  • You have 45 minutes to create a new, static visualization from the pie chart provided.
  • You can use any tool you wish [Note: students were introduced to Tableau a couple of days ago and we spent some time extending their data visualization capabilities in Excel].
  • If the data are hard to read or incorrect, do your best to ballpark it. If they sum to something other than 100%, make your own adjustments, add an Other category, whatever makes you happy, but make sure the categories in your visualization sum to 100%.
  • Give the visualization a descriptive title. If no title is given in the original pie chart, make one up. If a poor title is given, fix it.
  • Send me a single image with your visualization next to the pie chart (screenshots are fine). I will then post it to my site.

Now that the exercise is over and students are working on their final assignment, here is what they produced. I haven’t reviewed these before posting, so feel free to be judge and jury. And Tweet out with Xan’s #OneLessPie hashtag if you like. Happy Pi Day!

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