Another delightful addition to the stuff-you-think-you-know-that’s-wrong genre, á la Freakonomics, Outliers, and The Black Swan.

Baseball players who have a good year usually do worse the following year, but bad players often improve. So the good players are slacking off, and the failures are trying harder, right? Wrong. It’s a mathematical law no different from the Pythagorean theorem. Everyone knows why brilliant men marry less-than-brilliant women, but why do brilliant women tend to choose less-intelligent men? Unlike Malcolm Gladwell, Steven Levitt, or Stephen Dubner, all of whom range over many topics, Smith (Economics/Pomona Coll.; Standard Deviations: Flawed Assumptions, Tortured Data, and Other Ways to Lie with Statistics, 2014, etc.) covers one big concept that almost everyone gets wrong: regression to the mean. Put simply, it means that for any action in which chance plays a role—e.g., taking a test, playing a game, running a business, governing, research—things even out. If you get an extreme result, the next result will probably drift toward the average. A distressing example: medical journals regularly publish studies of effective treatments that, once approved, don’t work as well (mammograms, antidepressants) and sometimes not at all (arthroscopic knee surgery). Eliminating chance from research is difficult. Journals prefer studies that find something. Scientists yearn for a breakthrough, so, if results aren’t impressive, they look again—and again. “If you torture the data long enough,” said British economist and author Ronald Coase, “it will confess.” Smith argues his case with more graphs, studies, examples, and math than necessary, and the end result may leave readers in despair—convinced that almost everyone, experts included, believes an important piece of nonsense and will continue to believe—unless they read this book.

A welcome, widely applicable follow-up to the author’s equally useful first book.

Read this book. Then give it to your family and friends. There is no other single idea that will better improve your understanding of the world, and judgement of the future, than regression-to-the-mean. Drawing on education, health, politics, business and sports, Smith shows us how others have gotten it wrong and how you can get it right.Cade Massey, Professor, Wharton School of Business

In clear, entertaining prose and the use of telling, useful, and even charming examples, Smith dissects one of the most fundamental principles of how the world works—and how our intuitions often fail to catch on. Anyone who wants to think more clearly and act more rationally will profit from reading this book. Tom Gilovich, Irene Blecker Rosenfeld Professor of Psychology, Cornell University, author of How We Know What Isn't So

Vagaries of chance are part of our lives, whether we like it or not. “What the Luck" presents serious stuff in an eminently readable and entertaining manner. Using colorful examples, it teaches humility for good fortune and hope after misfortune. A wonderful reading! Cristian Calude, Professor of Computer Science, University of Auckland and Giuseppe Longo, Centre Cavaillès, CNRS et Ecole Normale Supérieure, Paris, and Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston

The beauty of this book is it sheds light on the need for humility when one experiences good fortune, and the importance of hope after misfortune. This nuanced understanding will help readers make better decisions in all realms of their lives. Jonathan Abelson, MD, radiation oncologist

As a lifelong sports fan I’ve always been puzzled by a phenomenon in which a team wins a championship and, after failing to repeat the next season, everyone from fans to management looks for what went wrong and begins trading players and changing strategies, thereby dooming the team to do even worse the season after. Gary Smith has solved this puzzle, and many more in all walks of life, through the concept of regression to the mean, one of the most powerful and least understood factors in how things turn out in life. You will not look at the world the same after reading this illuminating book.Michael Shermer, Publisher Skeptic magazine, columnist Scientific American, author of The Moral Arc and Why People Believe Weird Things

If you can combine the insightful lessons of this book with equanimity in decision-making, your foresight may become remarkable—and it won't be due to luck.Michael Solomon, Partner, Leonard Green & Partners, Private Equity

What the Luck? is a must read for those in the healthcare profession. We are constantly inundated with research on the latest and greatest therapy and understanding regression toward the mean can help us better interpret and apply this research to the daily care of our patients. Robert Sallis, MD, Director of Sports Medicine, Kaiser Permanente Medical Center, Fontana CA, Clinical Professor of Family Medicine at UC Riverside School of Medicine, Past-President of the American College of Sports Medicine (ACSM) Chair of Exercise is Medicine®, a joint initiative of ACSM and the American Medical Association

Wish you had made it less interesting so I’d be able to put it down and go to bed. I’m so glad you decided to write about regression towards the mean, because this is the key to the universe. Of course, learning about this is like a blessing and a curse. Once people have digested this book, they will absolutely see regression everywhere and understand its effect, but they will also be driven crazy, as you undoubtedly are, when they hear all of the unsupported and sometimes absurd explanations people cling to in order to make sense of it. Great job! Jay Cordes, Data Scientist

Gary Smith's What the Luck alerts us to many subtle and unappreciated consequences of one of life's great truths: it has its ups and downs.George Akerlof, Georgetown University, Nobel Laureate in Economics 2001

After reading What the Luck, you will appreciate how to separate the sense from the nonsense when it comes to making decisions about your health, your money, your test scores, or your favorite sports team. Written with accuracy and humor, I highly recommend it. Arthur Benjamin, Professor of Mathematics, Harvey Mudd College, Author of "The Magic of Math: Solving for x and Figuring out Why”

Given the high quality of Gary Smith’s previous work, I was expecting this new book to regress to the mean, but it performed well above replacement level throughout. Decision makers everywhere should read it to avoid making the mistakes of their predecessors.Andrew Gelman, Professor of Statistics and Political Science, Director of the Applied Statistics Center at Columbia University

What the luck? is a fabulous, funny and completely accessible explanation of the pervasive misreporting and misunderstanding of what statistics really mean in common discourse. If you are interested in what is really going on in sports, gambling, genetic inheritance and everything else that is misrepresented statistically in public discourse, you will love this book. I wouldn't wait for the TV miniseries, I'd take What the luck? to bed now. Bruce Chapman, Professor of Economics, Australian National University

Humans are prone to search and “find” causal drivers of the events that shape our lives. In reality, we are impacted by chance more often than we think. Professor Smith uses simple reasoning and vivid examples to help us decipher truth from fiction, thereby helping us to make better decisions.Bryan White, Founder, Sahsen Ventures

This book deeply enriches readers' understanding of the ubiquitous role of chance in everyday life. The book is so wonderful that I predict the author's next book will be less wonderful. Why the pessimistic prediction? This book will painlessly—even enjoyably—teach you why. Michael Murray, Charles Franklin Phillips Professor, Bates College

What the Luck? is a humorous, entertaining book citing real life examples, from areas as diverse as gambling, sports, scholastic achievement, medicine and the stock market to explain how randomness and "luck" are far more prevalent in our daily lives that we may realize. Reading this book also helped remind me that regression is often a more meaningful driver of stock (and bond) performance than the underlying business fundamentals. This is an important lesson for any serious investor. Mike Schimmel, Portfolio Manager, Kayne Anderson Capital Advisors

Gary Smith has another winner! His ability to combine entertaining writing with meaningful analysis should put him at the top of every thinking person's reading list.Woody Studenmund, Laurence de Rycke Professor of Economics, Occidental College

Smith provides a fascinating and accessible overview of regression toward the mean in sports and other domains. If you play fantasy sports, you should go get a copy of the book at once (while hoping your competitors have not done likewise).Alan Reifman, Texas Tech University, author of Hot Hand: The Statistics Behind Sports’ Greatest Streaks

Gary Smith's new book on regression to the mean is a much-needed corrective for the nearly universal human tendency to confuse what's systematic in life with what's mere chance. Absorbing Smith's message will help us avoid common but costly mistakes like putting too much of our wealth in investments that have little probability of out-performing the market, or expecting ourselves (or others) to perform in ways we (or they) can't, or feeling guilty for what happens that isn't really our fault. Lots of people everywhere can benefit from the principle he so clearly explains, and many of the concrete examples he uses to illustrate it will strike home. Benjamin M. Friedman, William Joseph Maier Professor of Political Economy, Harvard University, and author, The Moral Consequences of Economic Growth

There is an infectious clarity of statistical reasoning in Gary Smith's work. His friendly, logical, systematic writing entertains and gives a confidence of membership in an inner circle as brilliant as Smith himself. Eric Engberg, Data Scientist and Software Engineer, Wells Fargo

What the Luck is a tremendously entertaining and revealing read. A quick and engrossing piece of work, it is a must read for those who approach the world with educated insight! Two thumbs up! Simeon Nestorov, CFA, Managing Director, Berkeley Square Inc.

Smith uses a wide variety of real-life examples to illustrate why conventional wisdom often fails to acknowledge that one of the most important ingredients is luck. Karl J. Meyer, Director of Strategy, Hewlett Packard Enterprise

Smith uses entertaining and intuitive examples to show how regression to the mean explains patterns in education, business and medicine. Anita Arora, MD, MBA, RWJF Clinical Scholar at Yale University

People often underestimate the impact of luck in their lives. What the Luck is eminently readable and entertaining, filled with colorful examples. Sebastian Thomas, Director, Head of US Technology Research, Allianz Global Investors

Few statistical concepts are as important to understand today as regression to the mean. Through fascinating tales, What the Luck? provides a panoply of examples of this essential phenomenon in sports, business, life, and more. I heartily recommend it. Phil Simon, award-winning author of Message Not Received: Why Business Communication Is Broken and How to Fix It, lecturer at Arizona State University’s W. P. Carey School of Business.