A data set that occurs frequently consists of the values or the percentage breakdown of several categories for two time periods. A common way of plotting these data is to use a pair of pie charts.

Pie charts are unique among the types of graphs Excel can make because they only work with limited sets of data. Unlike bar charts and line charts, two or more pie charts do not combine easily, ...

Edward Tufte hates pie charts. Edward Tufte is also the only chart theorist normal people have ever heard of. And so yesterday the Internet was gripped with anti-pie fervor. My friend Tom Lee sticks ...

The Enlightenment gave us many foundational ideas: Gravity! Democracy! Infographics! Wait, what? Yep. One of the age’s lesser-known byproducts was the niche field of “graphical statistics,” aka data ...