Book Review

720 0197-2456/91/$3.50

Presentation of Clinical Data. By Bert Spilker and John Schoenfelder, Raven Press, New York, 1990, 553 pages, $80

Most statistics books necessarily have little space to discuss tabular and graphical display of data. I suspect that authors assume or hope that readers will absorb the principles indirectly by means of the examples. I am not aware of any previous book devoted to the presentation of clinical data, so these authors had the field to themselves. Despite the size of this book (553 pages with about 350 figures and 250 tables), its most serious problems arise from under- rather than overambition by the authors. Specifically, it is, as the authors admit, a catalogue rather than a treatise: "The purpose of this book is to illustrate formats that may be used for the presentation, rather than the analysis, of data. Data analyses and statistical presentations are not de- scribed."

There are two serious problems with the book, both already alluded to. First, there is almost no critical discussion of the examples. Thus, hundreds of examples from the literature are reproduced with minimal comment. Fur- ther, only rarely are alternative displays of the same data illustrated. I was hoping for discussion of the good and bad features of different types of display. Good and bad are present, but it is up to the reader to work out which is which. Thus, for example, misleading three-dimensional histograms and pie charts are included but not criticized. The common dreadful practice of summarizing continuous data simply as a vertical bar representing the mean level is endorsed, even with scale breaks (e.g., figure 10.2). Some im- portant general issues are not discussed, such as numerical precision in tables and scale breaks in graphs (especially histograms). The authors finally do consider "complex or confusing" presentations, but too late and much too briefly.

Second, the attempt to divorce data presentation from statistical issues does not seem to work. Simple issues, such as when to prefer standard errors or standard deviations, are not addressed. Many of the graphs contain sta- tistical material that is confusing. For example, figure 8.58 shows a regression line but erroneously gives the regression equation as predicting y rather than lOgl0y. Figure 9.16 also shows a regression line, with the text "s 1 = 1.51 (p < 0.01)" and "rl = 0.02." The first value seems to be the slope but I can't identify the second. The caption of this figure is: "Illustrates superimposing (only when appropriate) the linear regression line on a scatter plot." We are not told when this is appropriate. Many graphs have undefined bars around estimates.

Much of the book is, at least implicitly, related to clinical trials, notably in the chapters "Illustrating Study Designs," "Adverse Reactions," and "Effi- cacy." However, there is no entry for "clinical trial" in the index, although

Controlled Clinical Trials 12:720-721 (1991) © Elsevier Science Publishing Co., Inc. 1991

655 Avenue of the Americas, New York, New York 10010

Book Review 721

there is one for "crossover study." Nor is "repeated measurements" in the index, although several figures address this topic, notably in chapter 9. Use of the book as a reference (surely the intended use) is not helped by these omissions. It is a sign of the times that a chapter is devoted to meta-analyses.

There are certainly some useful features here. For example, chapter I pre- sents guidelines for preparing tables and graphs, most of which are sensible. Nevertheless, I feel that this book represents a missed opportunity.

Douglas G. Altman, BR Imperial Cancer Research Fund

PO Box 123 Lincoln's Inn Fields

London WC2A 3PX, UK