Arrow charts and slope charts are alternatives to multiple pie charts when the data consist of the values or the percentage breakdown of several categories for two time periods.

Back in 2012, The Salt surveyed readers on their favorite pies during our Pie Week series. Recently, an Australian reader tells us she pie-charted our results with mouth-watering real pie.

They are popular because they are popular, which is a circular argument that suits a pie chart. But there are some serious downsides to using the humble pie. Here’s why you should (almost) never ...