Book Review: Scorecasting by Moskowitz and Wertheim

Scorecasting is one of these books like Nudge and Freakonomics that is just pure pleasure to go through, page after page. The focus here is on sports. The academic author is professor of finance at U of Chicago, the journalist works for Sports Illustrated. What a great duo. The number crunching is brilliantly merged with anecdotes to make derangingly-convincing arguments. The longest chapter debunks the reasons behind the home-field advantage, i.e. the fact that in every sport, from basketball to international cricket, the home team wins more than 50% of the games. Most would guess this comes from players playing better at home as they have the backing of fans, they know their field, and they’re not tired from travelling. The authors rule against these explanations one by one, for example by analyzing all kinds of player-performance indicators, and finding no difference between home and away.  They then argue referee bias is actually the main reason behind the advantage. That is because referees are in essence human, and they unconsciously wanna please the crowd. Using baseball data, they show that umpires are more likely to favor the home team on tough calls, where the line between a ball and a strike is very thin. When there are no fans, such as in 21 games in Italian soccer in 2007, they show that players at home play as well as away, as usual. However, the home bias in favorable calls drops by 23%. They explain these phenomena using insights from behavioral economics, such as loss aversion, the endowment effect, or the omission bias. The latter may explain why referees often swallow the whistle so as not to decide the outcome of a game, like when a foot fault was called on Serena Williams in the last game of her semi-final at the US Open… the call was right, but fans would rather have seen an everlasting rally. Serena let the line judge understand that it was a bad idea. Squeezing the ball in her hand, she gently told her: “If I could, I would take this fucking ball and shove it down your fucking throat”.