Book Review

The Illusion of Certainty: Health Benefits and Risks

N Engl J Med 2008; 358:1082March 6, 2008

Article

The Illusion of Certainty: Health Benefits and Risks
By Erik Rifkin and Edward Bouwer. 239 pp., illustrated. New York, Springer, 2007. $79.95 (cloth); $29.95 (paper). ISBN: 978-0-387-48570-6 (cloth); 978-0-387-75165-8 (paper).

This book describes not only the principles of calculating basic epidemiologic risk estimates, but also how different presentations of the same research affect the interpretation of disease risk. One of the main messages of the authors is that the public, politicians, and other decision makers need professional guidance when they make evidence-based decisions about health screening and medical interventions and when they decide how to act on environmental health hazards.

The Illusion of Certainty — the title goes straight to the point — is well written and progresses logically by tying the subject and the facts around fictive and real case studies. The basic methodologic principles can be found in statistical and epidemiologic textbooks, but what differentiates The Illusion of Certainty from these other books is the use of cases to answer such questions as whether the benefits of a mammogram are worth the time, money, and potential negative impacts from intervention. Some case studies might be familiar, but the text keeps the reader interested and offers new angles from which to view health risks and benefits and the assessment and management of risk — especially from the consumer's point of view. The authors introduce the difficulties and the potential — sometimes inevitable — weaknesses of research, and they discuss how the manner in which risks are characterized can lead to a wide range of outcomes.

This book illustrates the difficulties that patients may have in understanding what the experts are telling them, especially when different experts appear to have different opinions based on the same studies. This may be due to the fact that results are often presented in a way that can lead to opposite decisions on questions such as whether or not to take serum lipid–lowering medication. Rifkin and Bouwer introduce an easy-to-understand platform that can be used to demonstrate the absolute risk of disease or the benefits of screening or treatment: a chart of a hypothetical, 1000-seat Risk Characterization Theater.

The theme throughout the book is how much uncertainty in research is acceptable to enable decision making, and how this uncertainty should be made more explicit when results are being described to the public. Reporting a benefit or risk value as a single number, as members of the media commonly do, often creates an illusion of certainty. The authors discuss how uncertainty or predictability can be illustrated in a simple way with the use of their Risk Characterization Theater graphics.

The examples that are used to introduce key issues vary from ecologic risk assessment (such as environmental contaminants) to screening for colorectal or breast cancer. Nevertheless, the authors have maintained the general theme of the decision-making process throughout the book. Readers may find this book controversial because uncertainty and lack of data lead the authors to leave many questions unanswered. Even so, it will improve the lay reader's understanding of risk and will be useful reading for medical professionals and those in related fields.

Marjo-Riitta Jarvelin, M.D., M.Sc., Ph.D.
Imperial College London, London W2 1PG, United Kingdom
m.jarvelin@imperial.ac.uk