Are you new to evaluation? Do you feel deficient in math? Do you fear using estimates in your analysis? If you answered yes to any of these questions, be sure to read this review of What the Numbers Say, as it may just be the book that can ease your evaluation challenges.

I have a favorite pasttime: perusing bookstores. My favorite section? Economics. It is in this section where you can find all the fun books; you know, those books about numbers, math, and econometrics, all the books that give us a basis for accepting uncertainty in data.

One of the fun books I often recommend is What the Numbers Say. Mathematicians and public-policy scholars Derrick Niedermann and David Boym have written a wonderfully enlightening book for anyone who places too much faith in any number and especially for those new to evaluation, those who feel deficient in math and fear the use of estimates in analysis.

The book begins with an introductory chapter: The Quantitative Information Age, which reinforces that we are inundated with data. But the authors tell readers that good quantitative thinking is not about being skilled at math, but rather being skilled at using the data strategically and being able to make rough estimates.

The authors then introduce the readers to The Ten Habits of Highly Effective Quantitive Thinkers, which is categorized into five themes that set the stage for the book:

Attitude Is Everything

Habit 1: Only Trust Numbers

Habit 2: Never Trust Numbers

Navigational Tools

Habit 3: Play Jeopardy

Habit 4: Live by Pareto's Law

Illuminating Numbers

Habit 5: Play 20 Questions

Habit 6: Build Models

Uncertainty

Habit 7: Play the Odds

Habit 8: Know What You Know and Don't Know

Estimation

Habit 9: Go Figure

Habit 10: Look for the Easy Way Out

Throughout the book, the authors provide examples of how data are developed and interpreted (or misinterpreted). For example, in baseball, the number of hits divided by the number of at-bats calculates batting averages. But there are hidden meanings behind the definitions of at-bat: Walks don't count as at-bats, neither does getting hit by a pitch. Getting on base due to an error in the field does count as an at-bat.

They also provide insight into how to take shortcuts to get to close-to-accurate calculations. For example, they introduce readers to the Rule of 72. Using the Rule of 72, you can estimate how long it will take your money to double (or for a population to double). For example, if your money is growing at a rate of 8 percent per year, divide 8 into 72 and you will find your money will double in nine years, a close estimate to the actual calculation of nine years, two days, eight hours, 39 minutes, and 46 seconds.

Throughout the book, the authors use examples like this to reinforce that exact answers cost time and money and often are unnecessary.

What the Numbers Say is an easy read. The book is full of examples and stories, some of which may surprise you and even disturb those who think in terms of absolute accuracy. If nothing else, the book that will have you looking at all numbers, including evaluation data, differently.