Tuesday 20 May 2008

Home team advantage in sports

Mark Koyama has an interesting post on The Causes of Home Advantage in Team Sports at the Oxonomics blog. Koyama writes
Jimmy Reade and myself have attempt to address the question of home advantage in football in this paper. We find that home advantage in English football has fallen since the 1980s.
He goes on to say
Drawing from Alchian and Demsetz (1972) we argue that players in team games have an incentive to free ride on the contributions of their team-mates. Fans monitor player performance and can single out players they feel are shirking.

How does this relate to the phenomenon of home advantage? We argue that
'Fans as a whole are better able to monitor individual player performance in home games than in away games because a far higher proportion of fans attend home games relative to away games. More specifically, they are better able to measure the effort an individual player exerts in a home game. Therefore average player performance will be higher at home games because shirking is more effectively deterred in home games.'
I hope the Crusaders, and their fans, keep this in mind on Saturday night!

As to the question Why has home advantage declined since the 1980s? Koyama explains
Well, in our argument what happened was television. This enabled supporters to better monitor their team when it played away from home. And this in turn reduced the extent of home advantage.

3 comments:

Matt Burgess said...

I have not read the paper, but missing from the quote is the all-important bit: what is the relationship between fan monitoring and player incentives? And could that possibly have an effect on incentives anything like as strong as having the team's manager, who is both an expert and holds the purse strings, at every game?

How about this alternative explanation: the introduction of individual player performance measurement has eliminated the ability of individuals to mask *from managers* poor individual performance in away games. If managers can quantify in absolute terms how far each player runs in a game and how many errors they make etc, then incentives away from home may be improved. That does not explain why performance falls in away games, but it might explain the recent away improvement.

Might superior home performance be explained as follows: a player has a finite amount of effort he can supply over a season and must allocate that effort to maximise some objective function, such as salary or probability of winning a contract next year. If home performance is a stronger driver of these objectives than away performance, which I suspect they would be as the ability of a team to draw a crowd depends much more on home performance than away, and therefore the value of a player at the margin depends more on home performance, a player will maximise the objectives by allocating effort towards home games and away from away games.

If an athlete is unable to "get up" for every game and has the ability to select which games to "get up" for, then it seems to me rational to select home games in favour of away games to do that.

I'm sure I'm not the first to suggest this. A test of this idea is whether home advantage persists in important one-off games like finals.

Paul Walker said...

Matt: The paper argues "But perhaps the most direct way of ensuring that players play well is supporter pressure. Fans watching a game live can easily detect when a player is shirking. For this reason we suggest that players put more
effort in, and play better when they are being watched by their own fans. Players who do visibly shirk are signalled out by the fans. Moreover players who are unpopular with the fans almost inevitably leave the club."

You say "the introduction of individual player performance measurement has eliminated the ability of individuals to mask *from managers* poor individual performance in away games." But manager have always be at games and thus have always been able to monitor player performance. So what has changed post-1980? What I don't see in your argument is why the home advantage should have fallen off since the 1908s. The use of tv to monitor players by fans would explain this.

Matt Burgess said...

But manager have always be at games and thus have always been able to monitor player performance. So what has changed post-1980?

My idea is that without statistics even an experienced manager will struggle to detect an individual's effort when that individual's teammates' effort has also fallen.

If a manager can call a player into his office and show him a 25% reduction in metres run in a game compared with last week, I wonder if that is infinitely more powerful.

The idea is testable. If the timing of the reduction in home advantage coincides with increased tv audiences and not the rise of player statistics then my idea is wrong.

I suppose another approach is to ask retired players (who are presumably more free to be honest) what motivates them when playing away from home.