Pie Charts: The Prime Evil

pie2.pngI’ve been busy working on edits for my recent paper, which attempts to present lots of data in relatively clear ways. I’ve gotten some great comments from readers. None more so than this one, in response to a proposed figure providing some descriptive statistics:

Pie charts are bad! They are ugly and provide the reader no visual assistance in comparing categories.

I had no idea if this was a generally accepted view among experts in the visual display of quantitative information. Extensive research suggested that it was:

One of the prevailing orthodoxies of this forum – one to which I whole-heartedly subscribe – is that pie charts are bad and that the only thing worse than one pie chart is lots of them.

The thing I don’t get is why: pie charts seem to be a very common form of data presentation; and folks are accustomed to measuring the area of slices of pie, so the visuals convey important data. What’s wrong with a slice of pie? (And, more importantly, are dot plots really better?)

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8 Responses

  1. Greg says:

    I don’t know about evil, but, here is the world’s best pie chart.

  2. Howard says:

    Well from your extensive research I think this makes it pretty clear. If two slices are similarly sized, it’s harder to see the difference in a pie chart vs a bar chart or table.

  3. Adam says:

    Use a bar graph, not a dot chart. It’s easier to compare the hieght of bars than the slices of pie.

  4. KipEsquire says:

    Pie charts are bad because they make people hungry for pizza and they are no longer able to concentrate.

  5. John says:

    See Edward Tufte.

  6. Homer says:

    mmmm, pizza.

  7. Belle Lettre says:

    “pie charts bad” has to be my new favorite boolean search term. It sounds like a judgmental baby researcher.

    Could be the next article title–although you just can’t beat your own “Best Puffery Article Ever.” You peaked early, dude.

  8. Sohnee says:

    There is quite a log of discussion on this topic – and the general feeling appears to be that pie charts were a bit of a mistake.

    http://www.stevefenton.co.uk/Content/Pie-Charts-Are-Bad/

    http://blog.jgc.org/2009/08/please-dont-use-pie-charts.html

    http://www.perceptualedge.com/articles/08-21-07.pdf (PDF)