Visual Explanations: Images and Quantities, Evidence and Narrative by Edward R. Tufte (review)

VISUAL EXPLANATIONS: IMAGESAND QUANTITIES, EVIDENCEAND NARRATIVE by Edward R. Tufte. Graphics Press, Cheshire, CT, U.S.A., 1997. 158 pp. $45.00. ISBN: 0-961-3921-26. Reviaued b Wiyred Nick Arnold, De/iartincnt o f Biochemistry oiid Molecular Biology, Universityo f Kansas M e d i c a l Center,Kansas City, KS, 66160-7421, U.S.A.I h a i l : . Pick up any issue of tliejournal Science and take a moment to evaluate their typical composite graph. After struggling to correlate the A’s, B’s, C’s and D’s of the component pictures with those buried in the ponderous figure legend, try to match the shapes (circles, squares, triangles; filled or open) of the data points with the conditions they represent (also in the legend), and hope that the acronyms and abbreviations will make sense (if you manage to find them in the main text). Let us concede that we are conditioned to put up with a lot of poorly presented inforination . If you are in doubt, try submitting your own simple graphs to thejournal with explicit labels on the curves, and be prepared for the editorial staff to amalgamate the items into confounding sets and to abstract the curve identifiers into the deadly legends. Another journal, Cell, elects to publish in fonts with no serifs ancl denies the wellfounded custom of using italics for Linnaean genus and species nomenclature. Perhaps the culprits believe that this “modern and crisp” style helps improve reader comprehension. In fact, controlled studies reveal the opposite. All of this is the more remarkable because editors are supposed to be engaged in an activity that improves clarity and logical explanation. I wish they would read Edward Tufte. VisiialExplanations is the third book in a series written and published by Tufte, a professor at Yale University. The first, The VisualUisfilay of Quuiitital i 7 ~ Data (1983),was both instructive and entertaining. I missed his book EnvisioninSInformntioiz (1990),but want to read it as soon as I can. The present volume is beautifully produced. Several examples, both old and current, are displayed, first as originals and then after improvement by Tufte and his associates. The results are entirely convincing. Even an icon such asJohn Snow’s statistical graphic on the 1854 cholera epidemic in London is analyzed without trepidation. The author dives into the data around the Broad Street pump (the source of infected water in the epidemic) and shows how various displays will more or less support the proper interpretation of the mode of transmission of cholera. On the other hand, the change in incidence of disease after the climactic removal of tlie pump-handle has been overly interpreted by other commentators in terms of cause ancl effect. Tufte succinctly and intelligently takes the reader through the logical possibilities and coincidences, without denying that the correct and constructive conclusion was reached by Snow. “There are right ways and wrong ways to show data; there are displays that reveal the truth and displays that do not.” Edward Tufte puts a fine point on this maxim by comparing the nineteenthcentury presentation of tlie cholera epidemic with the data displays behind the disastrous 1986 explosion of the Challenger space shuttle. The latter incident was attributed to the failure of two 0rings at low temperature, and the good professor shows us how the now-obvious indicatioiis of potential problems were hidden under unproductive data summations . The serious need for good visual and statistical thinking could hardly be exemplified more forcibly. to disinformation design, wherein the ingenious mechanisms of magic are used to show how information is intentionally hidden, and thus reveal, by contrast, the principles that should be avoided when the object is to communicate the truth. The final chapters are “Multiples in Space and Time” and “Visual Confections.”The latter refers to “assembliesof many visual events,” some of which are charming as well as instructive. Others are delightful, not least of which is a reproduction of Mark Tansey’s painting, iVJytli o f De/itIi (1984), wherein five contemporaries ofJackson Pollock display their own various and revealing aspects of body language as they contemplate the artist’s apparent ability to walk on water. This...