Last week I wrote about the Top 100 Goalscorers In Premier League History. It was a fun exercise and, crucially, it didn’t swallow my time or destroy my life like the sourcing/analyzing/publishing of some other stats can. So, as one does, I thought I’d repeat the goalscorer investigation, but examine goalkeepers instead.
I recorded four separate numbers:
- Goals Against
- Shots on target against
- Save% (100-goals against/shots on target against)
I recorded these stats for every player who played as a goalkeeper between the seasons 2010/11 and 2013/14 (no accurate data before 2010). I also recorded each players age.
2903 games played by goalkeepers.
13209 shots on target against.
4013 goals against
Only 75 goalkeepers played in the league between 2010/11 and 2013/14 and that number is is pretty insufficient really. There’s a slight curve here if you were to normalize the four skyscraper seasons, but there’s just a lot of noise here due to the small n of players.
Young ‘keepers just didn’t play in the PL in the 4 seasons I looked at. We also see a drop off after age 31.
A similar trend: the young guys and the old guys didn’t concede that many goals because, simply, they didn’t play too much.
Shots On Target Against
Same trend again: young guys don’t play, old guys play less.
What we really need to look at now is Save%.
Save% (goals against/shots on target against) is a pretty noisy statistic, it isn’t particularly repeatable year on year, it is a very team dependent stat but I what I want to know is if there’s any actual talent wrapped inside that noise.
If there is talent in save% then it may be fair to say that there’s a peak talent level for goalkeepers. All footballers, whatever the position, will have development years as youngsters, peak years where their experience and physical condition coincide, and post peak years where the reflexes decline. Agreed?
If there is a peak for goalkeepers, and there surely must be, then Save% isn’t capturing it. Maybe it’s the small n, maybe it’s that goalkeepers don’t matter too much, maybe it’s too team dependent, maybe it’s too luck driven, but whatever it is save% for each age bucket barely changes from development player to “peak” age to post peak age.
From ages 20 to 31 save% is virtually flat, with never more than a 2-3% change either way.
So if save% doesn’t capture goalkeeping talent, and the age curve of that talent, then what will? I’d try to somehow increase the n of this study first of all. But what else could we use to try to identify an age curve? Shot location? Reflex time? Save% when the goalkeeper is shifting?Save% vs expected save%? I’m at a bit of a loss.
The Best (and worst)
|Van Der Sar||32||114||71.9|
If anyone spots any errors, let me know.