This is a fantastic evaluation by Bill Reno on americansocceranalysis.com – looking at keepers across the MLS in 2015.
Not only does he evaluate GAA and Save % metrics, he also compares them Shot Difficulty, Goals and Expected Goals for a very in-depth evaluation of MLS keeper performance. The biggest insight into GAA which struck me is that he rightly points out that it’s a team stat, not an individual stat. Even over the course of a season, it has little or no relevance to GK ability. Save Percentage provides a slightly more predictable link to keeper performance over time but gives little insight into the how or why.To quote Bill Reno, “In the short term we only have the eye test to choose from “good game” or “absolute awful”.”
The beta version of Stopper is undergoing final tweaks to the Stats programming and debugging this week – look forward to doing some real world testing soon! While Stopper is intended for developing players, we’re curious to see how it evaluates professional players as well. It’s too late to get in on Championship League action but we’ll be testing it out on some MLS teams – let us know if you’ve got a favourite GK you want us to track!
Full article here: http://www.americansocceranalysis.com/home/2015/6/9/save-percentage-vs-goals-against-average-battle-royal