When you think dashboard graphics and dashboarding metrics, the ubiquitous pie chart graph probably comes to mind first. It must be the most widely used chart in the business world. Every school child is taught to read on and every business powerpoint has one in it.
The recent issue of Stephen Few’s Visual Business Intelligence Newsletter features a lead article on this classic business graphic. The article is comprehensive – I would consider it the definitive treatise on the pie chart. It covers the interesting history of the chart and most importantly, it offers many good reasons why you should NOT use this common graph form.
Few first starts off with the history of the little pie chart. Take a look at this first known usage of the pie chart:
That pie chart appears in 1801 in a publication by William Playfair called The Statistical Breviary (great last name for a statistian, don’t you think? It’s one of those ironies of history.) Playfair also introduced the use of the venerable bar graph.
Here is a closer look at one of Playfair’s pie charts:
For more of the history of the humble pie chart, see the Stephen Few article, Save the Pie for Dessert. It’s the latest in Few excellent newsletter series. To receive future issues, sign up at the Perceptual Edge site.
In terms of whether or not to use the pie chart, good additional information can be seen at the wikipedia pie chart article. The section “Discussion on Use” explains that statisticians tend to regard pie graphs as poor vehicles for displaying information. Did you know that research shows that comparison by angle is less accurate than comparison by length. Take a look at this comparison:
Tags: Pie Chart, Stephen Few Newsletter, Dashboard Metrics, Pie Graph, Dashboard Graphics