Home Field Advantage in MLS (and Goals Scored Home vs Away)
|EDIT 7/17/08: Edited to include full 2007 stats.|
In the nearly 2,000 MLS games over the past 11.5 seasons, playing at home has certainly been important (like in any sport). But just how important has it been? That's what I've attempted to find out, and in this update of a similar post from last year, I'll provide the numbers. This is not an examination of what causes home field advantage, but rather exactly what that advantage has resulted in on the field.
Throughout MLS history, the average PPG by every team in every game is 1.385. That's the basic equivalent of a .500 team (I find that it's much easier to use PPG rather than winning percentages in soccer). Actually, it's probably a little less due to the lower number of draws in the early years and also thanks to overtime from 2000-3. It's about 1.36 over the last four years.
So that's average of every team in every game, 1.385. That means there's an average of 2.77 points taken from any one game, which is less than 3.00 because of draws. The table below breaks that down into home points vs away points, and then the final column on the right is the difference between the two, aka home field advantage.
The all time home field advantage in MLS is 0.67 PPG. In other words, that translates to 20 points over a 30 game season. In general, the HFA seems to have been higher in seasons with more parity, which is understandable. Just look at how it dipped in 2005, when there were two absolutely awful teams and two really good ones. I guess I'll need to figure out the variance (or whatever) for each season and compare it to HFA in the future.
Performance of Home Teams in MLS
If you want to look at it another way, home teams get 62.2% of the points. I suppose that this actually a better way to look at home field advantage, since it takes out the affect that the number of draws has on PPG. To clarify, what I mean is that the total number of PPG will be different each year (i.e. 2.75 this year, 2.71 last year).
Home Point Percentage
I've gone a little further this year and taken a look at exactly how many goals are scored both home and away. On average throughout league history, the home/away breakdown is 1.75 vs 1.28, for a 0.46 goals per game difference.
Goals Scored by Home Teams vs Away Teams
Let's break this down into percentages too. So basically, a very small change in the percentage of goals from year to year. Not too shocking when you consider this is over anywhere from 140 to 192 games.
Home Goal Percentage
One last thing, I want to see how the the home point percentages compare to the home goal percentages. Can we gather anything from that? The two are obviously related, but this appears to show that given the percentage of home goals this season, home teams should really be doing better.
Maybe that's due to the number of blowouts? There have been 11 home wins of 3+ goals in 2007, versus only one away win of 3+ goals. A quick check, and I believe last year it was 15/5 (home/away).
Home Point Percentage vs Home Goal Percentage
For comparison purposes, last year in the Premiership in England, the home/away difference was 0.65 PPG. Home teams won 61.8% of total points. The home/away goal difference was 0.46 per game. Home teams scored 59.3% of total goals.