The Flaw of Averages

As the recent collapse on Wall Street shows, we are oftenill-equipped to deal with uncertainty and risk. Yet every day webase our personal and business plans on uncertainties, whether theybe next month’s sales, next year’s costs, ortomorrow’s stock price. In The Flaw of Averages, SamSavage­known for his creative exposition of difficultsubjects­ describes common avoidable mistakes in assessingrisk in the face of uncertainty. Along the way, he shows why plansbased on average assumptions are wrong, on average, in areas asdiverse as healthcare, accounting, the War on Terror, and climatechange. In his chapter on Sex and the Central Limit Theorem, hebravely grasps the literary third rail of gender differences.

Instead of statistical jargon, Savage presents complex conceptsin plain English. In addition, a tightly integrated web sitecontains numerous animations and simulations to further connect theseat of the reader’s intellect to the seat of theirpants.

The Flaw of Averages typically results when someone plugsa single number into a spreadsheet to represent an uncertain futurequantity. Savage finishes the book with a discussion of theemerging field of Probability Management, which cures this problemthough a new technology that can pack thousands of numbers into asingle spreadsheet cell.

Praise for The Flaw of Averages

“Statistical uncertainties are pervasive in decisions wemake every day in business, government, and our personal lives. SamSavage’s lively and engaging book gives any interested readerthe insight and the tools to deal effectively with thoseuncertainties. I highly recommend The Flaw ofAverages.”
—William J. Perry, Former U.S. Secretary ofDefense

“Enterprise analysis under uncertainty has long been anacademic ideal. . . . In this profound and entertaining book,Professor Savage shows how to make all this practical, practicable,and comprehensible.”
—­Harry Markowitz, Nobel Laureate inEconomics