Bashing pie charts seems to be a common topic of conversation to bond over for data geeks - like complaining about public transit or traffic for the rest of us. Why all the hate? Although there seems to be at least one pie chart in every report or newspaper you read, they actually have a much narrower range of use than we’d expect. Pie charts can be effective for high level takeaways involving a couple of categories, like in comparing % of respondents who said yes vs no. In cases like this we probably don’t care so much that 51% voted yes and 49% voted no, but about whether people responded yes significantly more, less, or about even as the others.
However, once we start caring too much about what that percentage breakdown is, or throw in another section (like % maybe), it’s a lot harder to get that information at first glance. Then, pie charts start generating questions like is that 27% or 29%? Are those all about a third? Or is one at 40% and another at 30%? At that point, most people would be better off with something like a bar chart. For a nice visual explanation of this, check out this article.