Sunday, 20 June 2010

Soccernomics

The football World Cup in South Africa has been going on for barely a week and it’s already generated more than its fair share of controversy. The players don’t like the ball because when they kick it, there’s no way telling where it will end up going (strangely enough, that is exactly what happens every time I play football too). And even if they could control the ball, they can’t concentrate on the game because of the constant noise of thousands of vuvuzelas. And then there is the woman who turned out to be a man… but hang on, that was a different competition.

So what is an economist’s view of football? Let’s start with the vuvuzela-blowing spectators. Cheering your own team and booing the opposing team gives you pleasure and makes you bond with your fellow spectators. It is also thought to give an important moral boost to the players, this is referred to as the home advantage: a team is more likely to win if they are playing at home rather than away. At the World Cup, South Africa would therefore enjoy an obvious advantage. Similarly, any country with a larger number of supporters than the opposing team would have an advantage. The North Korean team, most notably, cannot count on too many vuvuzelas cheering them.

But is it really the players who are subject to the home advantage? A recent paper by Mikael Priks and Per Pettersson-Lindbom of Stockholm University (Behavior under Social Pressure: Empty Italian Stadiums and Referee Bias, Economic Letters, 2010) suggests it is in fact the referees who are influenced by noisy spectators. How do you go about testing this? The answer is simple: let some games be played without spectators (treatment group) and compare the actions of the referees in those games with those played with spectators (control group). Of course, few clubs would accept this: they would loose both the home advantage and revenue from ticket sales. Instead, Priks and Pettersson-Lindbom managed to find what is referred to as a natural experiment. In 2007, the Italian government responded to an incident of hooligan violence by banning spectators from games at stadiums that did not meet minimum safety standards. As a result, a small fraction of games in Southern Italy were played without any spectators. Using this variation, they found that the referees behaved differently depending on whether spectators are present or not. In particular, the away team is punished more harshly (in terms of recognizing fouls and issuing yellow or red cards) when spectators are present. In contrast, they found no difference in the player’s behavior. In other words, the home bias is important but not because it boosts the home team’s performance. Instead, Priks and Pettersson-Lindbom argue, the referees are susceptible to social pressure from the crowds. So those complaining about the noise of the vuvuzelas are right and wrong at the same time. The vuvuzelas are affecting the outcome of the game but not because they distract the players or affect their concentration. Such an effect would presumably affect both teams equally and therefore it would be neutral with respect to the game‘s outcome. The vuvuzela effect is much more sinister: it can potentially bias the decisions of the referees in favor of the team with more numerous and more vocal supporters.

Another important complaint with this year’s World Cup has been the low number of goals scored in most games. This lowers the spectators’ enjoyment and leads to a relatively large number of games ending up in a tie. Some commentators attribute this to the already-mentioned balls used this year, which the players supposedly have a hard time controlling. Another explanation is that this is a an outcome of the players utility maximization. To score goals, players need to play aggressively, which is costly: it requires physical effort, increases the risk of injury and you risk spreading yourself too thin and thus giving the other team an advantage if they get possession of the ball. As a result, both teams have an incentive to play cautiously and defensively. In an attempt to alter this incentive, the payoff to winning has beeny increased from 2 points to 3 (a draw brings 1 point to each team) but that does not seem to have done the trick. A recent paper by Juan Carrillo (“Penalty Shoot-outs: Before or after Extra-time?” Journal of Sports Economics, 2007) suggested a further rule change: penalty shoot-outs should take place before rather than after extra time, with their outcome binding only if extra time ends in a draw again. This increases the stakes and alters the incentives of both teams: rather than both playing cautiously, the team that lost the penalty shoot-out now has an incentive to play an aggressive game while the other team needs to be defensive. This prediction, however, is only theoretical: would it also hold in practice? And how is it going to affect the outcome of the game? When one team plays more aggressively while the other team becomes more defensive, it is not a-priori clear whether this should leads to the aggressive team scoring more goals or the defensive team warding off such goals.

Lian Lenten, Jan Libich (La Trobe University) and Petr Stehlik (University of Western Bohemia) think they found a way to test this (“Penalties Before or after Extra-time? An Empirical Assessment of Footballers‘ Incentives,” manuscript). They point out that the proposed scheme is similar to the away rule whereby, if extra time ends in a draw, the team which scored more goals in away games wins. Scoring a goal during the first few minutes of extra time changes the incentives of the two teams in the same way. In either case, one team – the one with the lower number of away goals or the one which conceded a goal at the beginning of extra time – has to play more aggressively while the other team needs to defend their advantage. They use data from thousands of games played in 2007-9 and find that the away rule or a goal during the first five minutes of extra time indeed increases the probability of scoring in extra time – by approximately 45-60%. Economics is the study of incentives. This research shows that by moving the penalty shoot-outs forward – and thus holding them more often – it is possible to alter the underlying incentives and indeed the game itself in such a way that the outcomes of penalty shoot-outs decide fewer games. The World Cup organizers should perhaps take a leaf out of economists’ book. The result will be a more interesting and more enjoyable game.

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