Calculated Risks

Every day ordinary people are confronted with statistically-based information that may mean the difference between life and death, freedom and prison, or economic hardship and financial security. Understanding the real significance of a medical test, which is never absolutely certain, or following complex arguments with probabilities, is often very difficult for us.

And indeed, in the face of modern statistical devices such as probabilities and percentages, Gigerenzer has discovered that even most doctors and lawyers are unable to reason clearly about risk. Yet, Gigerenzer insists that any person of normal intelligence can understand risk without taking a course in statistics. In this book the cognitive psychologist offers simple tools that anyone can use to overcome innumeracy and understand the uncertainty in everything form medical diagnoses and DNA evidence to financial statements and political claims.

The books gives many examples, from the O. J. Simpson trial to the utility of breast cancer screening programs, and explains how the frequent misconceptions about risk are exploited.


UK edition: Reckoning with risk: Learning to live with uncertainty. London: Penguin Books, 2002

German translation: Das Einmaleins der Skepsis: Über den richtigen Umgang mit Zahlen und Risiken. Berlin: Berlin-Verlag, 2002
Italian translation: Quando i numeri ingannano: Imparare a vivere con l`intercertezza. Milano: Raffaelo Cortina, 2003
Japanese translation: Hayakawa Publishers, 2003
Portuguese translation: Calcular o risco: Aprender a lidar com a incerteza. Lisboa: Gradiva, 2005
French translation: Penser le risqué: Apprendre a vivre dans l’incertitude. Editions Markus Haller
Korean translation: Sallim Publishing Co.

E-book, Penguin (in press)


Till Grüne-Yanoff Till Grüne-Yanoff


Gigerenzer, G. (2002). Calculated risks: How to know when numbers deceive you. New York: Simon & Schuster.

ISBN-10: 0-74320-556-1
ISBN-13: 978-0-74320-556-6

Calculate Risks Cover