Scorecasting (22 page)

It had the makings of a nearly perfect day.
Jack Moore had just finished his sophomore year at the University of Wisconsin and was home for a few summer weeks, living with his folks. Marooned in the Mississippi River town of Trempealeau, Wisconsin, Jack was blissfully free of pressure, with generous rations of free time. He had a job coaching
baseball, but the games didn’t start until the evening. On this Friday of the 2009 Fourth of July weekend, Jack’s beloved
Milwaukee Brewers were playing an afternoon road game against their rivals the
Chicago Cubs.

Air-conditioning blasting, Jack flicked on the cable to the regional sports network and sat down on the couch to watch. The Brewers were coming off a magical 2008 season in which they won 90 games and reached the playoffs. In the off-season, Milwaukee’s ace, C. C. Sabathia, was poached by the Yankees. It was the numbingly familiar fate of a small-market team: The Brewers had been unable to match New York’s $161 million contract offer. Jack was okay with that. A math major, he knew the economic realities
and understood why Milwaukee could not afford to retain a star at those prices. Besides, the Brewers’ 2009 incarnation was easy to root for, a fun team with a winning record, filled with young and energetic players.

The game was a rare Wrigley Field pitching duel pitting the Cubs’ ace,
Carlos Zambrano, then a Cy Young Award candidate, against Milwaukee’s veteran
Jeff Suppan. The game was tied 1–1 after nine innings, which was all good with Jack, a former high school baseball player who was thoroughly capable of appreciating a low-scoring affair. “It was one of those games,” he recalls, “that remind you why you like baseball so much.”

Then, in the bottom of the tenth inning, Jack’s idyllic afternoon was ruined. The Brewers had summoned
Mark DiFelice, a right-handed pitcher who had recently won his first Major League game at age 32. When the Cubs loaded the bases, DiFelice faced Chicago’s third baseman,
Jake Fox, a utility man who’d ricocheted between the majors and the minors. With a full count, two outs, and the decibel level soaring at Wrigley Field, DiFelice threw four consecutive pitches that Fox fouled off. On the next pitch of the at-bat, DiFelice reared back and fired a cutter that froze Fox and shot past him. After an awkward pause, home plate umpire Bill Welke popped up from his crouch and … stood idly. Ball four. The winning run had been walked home: Cubs 2, Brewers 1.

The crowd goes wild. Jack Moore of Trempealeau, Wisconsin, goes ballistic. “For five minutes, I just screamed words you can’t print,” he says. “Anyone who knows baseball knew that was a strike.” For years, fans in Jack’s position would bitch and moan and dispute balls and strikes until last call. But this was 2009, and Jack wasn’t interested in an argument; he was interested in a straight, objective answer. He fired up his Internet browser, logged on to
MLB.com
, and clicked on Pitch f/x. Sure enough, DiFelice’s pitch was gut-high and clearly within the upper-inside part of the strike zone. Minutes after the game had ended, right there in his parents’ home in small-town Wisconsin, a 19-year-old was able to confirm his suspicions. The ump had blown the call, permitting the home team to win.

What sports fan doesn’t harbor a belief that the officials are making bad calls against his or her team? It’s a home crowd that voices this displeasure the loudest. The criticism ranges from passably clever (“Ref, if you had one more eye, you’d be a Cyclops!”) to the crass (“Ref, you might as well get on your knees because you’re blowing this game!”) to the troglodytic (“You suck!”). Dissatisfaction is voiced individually and also collectively, often in a stereo chant of “Bullshit! Bullshit!” In Europe—quaint, civilized Europe—there are even various soccer websites that enable fans to download antireferee chants as ringtones.

What we’ve found is that officials
are
biased, confirming years of fans’ conspiracy theories. But they’re biased not against the louts screaming unprintable epithets at them. They’re biased
for
them, and the bigger the crowd, the worse the bias.
In fact, “officials’ bias” is the most significant contributor to home field advantage
. “Home cooking,” as it’s called, is very much on the menu at sporting events.

A statement like that had better have some backing, and we’re prepared to provide it. Warning: An assault of numbers awaits. But stick with us and we’ll walk you through it. We think the payoff is worth it.

Let’s start by determining how to measure ref bias. You could examine the accuracy of calls made by the officials and whether that accuracy differs for calls favoring the home team versus the away team. But doing that is a challenge because it requires a great deal of subjectivity as well as a deep knowledge of the circumstances of the game. Was it really a foul? Was it really pass interference? What else was happening during the game at that time? In light of the speed of the game and the reactions of players within the game, it is nearly impossible to control for all the potential factors that could lead to differing calls for the home and away teams.

Suppose we find that more fouls are called against road teams
than against home teams—which, by the way, is often the case. Does this indicate a referee bias in favor of the home team? Maybe, but not necessarily. What if teams play more aggressively on the road? After all, road teams know that statistically, they are already more likely to lose. Or what if the road team, exhausted from those back-to-back games, lacks the energy for proper defense and clutches and grabs instead? They might be inclined to commit more fouls regardless of any referee bias, and so it’s difficult to identify the
causal
factor. Are referees
causing
more road team fouls because of bias against the road team? Or are players causing referees to call more fouls because of more sloppy or aggressive play? Or is there a third factor causing both?

We looked for a component of the game the refs control that isn’t influenced or affected by players. We found it in a sport for which we have not had much success in explaining its sizable home advantage—
soccer. It also turns out that had it not been for a diligent grandmother from Spain religiously watching and recording years’ worth of Sunday evening matches, we might not have discovered this bias at all.

In soccer, the referee has discretion over the addition of extra time, referred to as “injury time,” at the end of the game to make up for lost time resulting from unusual stoppages of play for injuries, penalties, substitutions, and the like. This extra time is rationed at the discretion of the head referee and is not recorded or monitored anywhere else in the stadium.

As best he can, the referee is supposed to determine the accumulated time from unusual stoppages—itself a subjective measure—and add that time at the end of regulation. So does the referee’s discretion favor the home team? If so, he would lengthen this time when the home team is behind at the end of the game and reduce it when the home team is ahead, extending or shortening the game to increase the home team’s chances of winning.

Using handwritten notes that his elderly mother had gathered logging matches she’d watched from her living room in Spain,
Natxo Palacios-Huerta, a London School of Economics professor, joined with two colleagues from the University of Chicago, Luis
Garicano and
Canice Prendergast—all soccer fanatics—to study the officials’ conduct during games. The researchers were, quite justifiably, struck by what they found. Examining 750 matches from Spain’s premier league, La Liga, they determined that in close matches with the home team ahead, the referees ritually shortened the game by reducing the extra time significantly. In close games in which the home team was behind, the referees lengthened the game with extra injury time. If the home team was ahead by a goal at the end of regulation, the average injury time given was barely two minutes, but if the home team was behind by a goal, the average injury time awarded was four minutes—twice as much time. Sure enough, when the score was tied and it wasn’t clear whether to increase or decrease the time for the home team, the average injury time was right around three minutes.

What happened when the home team was
significantly
ahead or behind? In games that were not close, there was no bias at all. The extra time added was roughly the same whether the home team was ahead by two goals or more or behind by two goals or more. This makes sense. A referee has to balance the benefit of any favoritism he might apply with the costs of favoritism—harm to his reputation, media scrutiny, and potential reprimands. Adding additional injury time when the score was so lopsided was unlikely to change the outcome and therefore accrue much benefit, so why do it and risk the potential cost?

The study also looked at what happened when, in 1998, the league altered its point structure from awarding teams two points in the standings for a win (and one for a draw and zero for a loss) to three points for a win. That change meant that a win was suddenly worth a lot more than it had been before and the difference between winning and tying doubled. What did this do to the referee injury time bias? It increased it significantly. In particular, preserving a win against the possibility of a tie now meant a lot more to the home team, and so the referees adjusted the extra time accordingly to reflect those greater benefits.

This wasn’t unique to Spain. Researchers began looking for the same referee biases in other leagues—not hard given the global
popularity of soccer. They found that the exact same injury time bias in favor of the home team exists in the English Premier League, the Italian Serie A league, the German Bundesliga, the Scottish league, and even MLS in the United States.

If referees are willing to alter the injury time in favor of the home team, what else might they be doing to help ensure that the home crowd leaves happy? We found that referees also award more penalties in favor of the home team. Disputed penalty shots and goals tend disproportionally to go the home team’s way as well. Looking at more than 15,000 European soccer matches in the English Premier League, Spanish La Liga, and Italian Serie A, we found that home teams receive many fewer red and yellow cards even after controlling for the number of penalties or fouls on both teams. The dispensing of red and yellow cards has a large impact on a game’s outcome. A red card, which sends the offending player off the field, reduces a team’s chances of winning by more than 7 percent. A yellow card, which precedes a red card as a stern warning for a foul and may therefore cause its recipient to play more cautiously, reduces the chances of winning by more than 2 percent. These are large effects. When a single yellow card, followed by a red card, is given to a visiting player, it means the home team’s chance of winning, absent any other effects, jumps to 59 percent. Add the injury time, fouls, free kicks … and it suddenly isn’t so surprising that the home team in soccer wins nearly 63 percent of its games.

But could this be limited to the idiosyncratic world of European soccer? Surely, American sports wouldn’t be subject to the same referee bias … would they?

Remember how, despite a significant home team advantage, athletes do not hit or pitch, shoot free throws, slap goals, or pass the football appreciably better at home than they do on the road? This prompts the question: What
do
home teams do better that allows them to achieve a higher winning percentage?

In baseball, it turns out that the most significant difference between home and away teams is that home teams strike out less and walk more—a lot more—per plate appearance than do away
teams. This could be for lots of reasons. One interpretation: Home team batters see the ball better or away team pitchers exhibit less control. But this contradicts our earlier results for batters and pitchers—in controlled, isolated environments, they hit and pitch the same at home as they do on the road. And as we’ve seen, road players in MLB aren’t performing worse because they’re exhausted from the travel.

Balls and strikes are the domain of the head umpire. Could the umpire be biased toward the home team? This would explain the differences in strikeouts and walks despite the lack of any difference in hitting and pitching.