No Humble Pie: The Origins and Usage of a Statistical Chart.

The article focuses on the origins and usage of a pie chart. The pie chart is more than two centuries old. The diagram first appeared as an element of two larger graphical displays in "The Statistical Breviary," whose charts portrayed the areas, populations, and revenues of European states. William Playfair had previously devised the bar chart and was first to advocate and popularize the use of the line graph to display time series in statistics. The first chart in the volume depicts the countries as they were before the French Revolution of 1789, and the second chart shows how these nations had changed by 1801. Circles of various sizes stand for the total land areas of the countries. While the land masses were indicated by the areas of the circles, the sizes of the populations were represented by the vertical red lines on the left of each circle and the tax revenues of each country were shown by the vertical yellow lines on the right. It is likely that pies, circles, and intersecting circles were such simple and familiar forms to Playfair that he did not think comment necessary. There seems to be little objective basis for a prejudice against the pie based on considerations of speed or accuracy of estimation-the pie chart does as well, if not better, on simple tasks such as the estimation of a single proportion or the comparison of a small number of proportions.