William Playfair (1759-1823) is generally recognized as the originator of now common statistical graphs such as line graphs for time series, pie charts, and bar graphs. But his books have not been generally available, and as Wainer and Spence start their preface: “…William Playfair’s Atlas is like the Bible: an ancient and revered book that is often cited but rarely read.” In addition to the Atlas, they also include Playfair’s The Statistical Breviary; shewing, on a Principle Entirely New, the Resources of Every State and Kingdom in Europe; Illustrated with Stained Copper-plate Charts, Representing the Physical Powers of each distinct Nation with Ease and Perspicuity.
Wainer and Spence have done us a great service by making Playfair’s two books available again. In their valuable 35-page introduction, they place Playfair’s life in the context of the times and also give us an historical account of his life. They discuss his graphs in light of how we today evaluate aspects of statistical graphs, and everyone interested in the theory of statistical graphs should read this introduction.
Most of the Atlas contains presentations and discussions of line graphs for time series, showing imports and exports between England and other European countries. He argues forcefully for the use of graphs instead of tables. The book is delightful reading, and the following quote, arguing for the use of graphs instead of tables, from his Introduction gives a strong flavor of the book (modernizing most of his f’s into s’s):
As the eye is the best judge of proportion, being able to estimate it with more quickness and accuracy than any other of our organs, it follows, that wherever relative quantities are in question, a gradual increase or decrease of any revenue, receipt, or expenditure, of money, or other value, is to be stated, this mode of representing it is peculiarly applicable; it gives a simple, accurate and permanent idea, by giving form and shape to a number of separate ideas, which are otherwise abstract and unconnected. In a numerical table there are as many distinct ideas given, and to be remembered, as there are sums, the order of progression, therefore, of those sums are also to be re-collected by another effort of memory, while this mode unites proportion, progression, and quantity, all under one simple impression of vision, and consequently one act of memory.
Nobody said it better during the next two hundred years.
Gudmund R. Iversen holds a PhD in statistics from Harvard University and is Professor Emeritus of Statistics at Swarthmore College where he taught statistics for many years