Long ago, when the Chicago Cubs played spring-training games in the desert city where I live, a friend and I would head to the park to watch the action. My friend was a savant of baseball numbers: He knew the results of every major-league veteran’s every at-bat and every rookie’s high school stats. He couldn’t predict the outcome of every play, but, his head stuffed with data, he could often call the final score well before the seventh-inning stretch.

In baseball, everything is measured. Everything. Measurement means money, and the players who rack up the big bucks are typically the high-number home-run kings and hurlers of mighty heat, not the quietly steady performers.

In Moneyball, published 20 years ago this week and a classic of both sports and finance writing, Michael Lewis argues that pro scouts usually measure the wrong things. Relying on gut instinct, they’ve favored big guys who hit with power and pitchers with a talent for loading the bases and leaving the runners standing there at the end of the inning—never mind their performance otherwise.

Enter Billy Beane, manager of the cash-strapped Oakland Athletics from 1997 to 2015 (and still a consultant for the team), who’d hired a young Harvard-trained math whiz named Paul DePodesta to scour the numbers and work the so-called “sabermetrics” with him. They discerned patterns that others overlooked while discounting “sight-based scouting prejudices”—“the scouting dislike of short right-handed pitchers, for instance, or the scouting distrust of skinny little guys who get on base.” DePodesta and Beane looked instead at things like “plate discipline,” the ability of a batter not to swing at everything the opposing pitcher throws, a strangely undervalued skill.

“There are smarter ways to play the game,” Lewis writes in Moneyball, and the A’s landed on one that relied not on gut feelings but on cold, hard data. Armed with numbers, the A’s hired players that scouts for other teams overlooked, getting a roster for bargain prices—one that outplayed most other teams with fatter budgets and, in 2002, won the American League West pennant in a 103-59 season.

Still in print, Moneyball was an instant hit. Among its closest readers were front office people in ballparks around the country, some of whom tried Beane’s methods even as MLB scouts huddled to figure out how to dismiss Lewis’ narrative and save their jobs. They didn’t have to worry, because most managers soon reverted to their old ways, not realizing, as Lewis writes, that “the statistics used to evaluate baseball players were probably far more accurate than anything used to measure the value of people who didn’t play baseball for a living.”

Twenty years later, front offices are trying to figure out how to get audiences in the stands, pro baseball having lost much of its popularity because of high ticket prices (driven, in part, by high player salaries). The A’s are on the way to Las Vegas, lacking the money to build a new stadium in the overpriced Bay Area. Their players are still paid less than most other clubs, but early in the 2023 season they were vastly outperforming superrich teams like the New York Mets—and doing it with skinny little guys who get on base.

Gregory McNamee is a contributing editor.