Stats Central

Think you know how possession in soccer is calculated? Someone with a stopwatch counts up the time each team has the ball, right?

https://chanceanalytics.com/2017/01/15/are-we-calculating-possession-all-wrong/

Think again. The number we see have nothing to do with time, and everything to do with counting possessions and dividing by the total number.

Throw out every assumption or conclusion you have ever made based on possession, since its nothing more than a passing stat. The guy in the article does it by time, and gets wildly different figures than the OPTA data showed.

Makes sense in our case since there have been times we've gotten dominated yet still had more possession. This pisses me off way more than it should.

Eh, one of the problems with calculating possession is that there are about a dozen different ways it's done and different places use different methods. That's why it's so frequent to see two sources disagreeing on the possession by as much as 10% or more on occasion.

http://www.slate.com/blogs/the_spot...ry_of_the_game_s_most_controversial_stat.html
 
Josh Saunders objectively sucks.

I took a look at keeper stats (through the 4/24 games). I tried to normalize performance by looking at things on a per minute basis (i.e. looked at goals allowed per minute of play for each goalkeeper). The other thing I did was used shots allowed per minute as a proxy for how good a team's defenders are. (I believe this is actually shots on goal, since obviously there are no keeper stats for shots that aren't on goal). The thinking is that a good defense allows fewer shots on goal.

What this let me do was try to separate goals allowed in terms of what's possibly due to a bad defense in general and what's possibly due to a bad keeper. Wanna know what I found? You do? OK - I found that NYCFC actually puts Saunders in a pretty good spot. NYCFC is tied for 3rd in shots allowed per minute of play - this is due either to NYC's stellar defense (?) or, maybe more likely, to the fact that they've actually possessed the ball pretty well.

View attachment 4779

And do you know how Saunders thanks his team? He ranks 17th in the league in goals allowed per minute of play (note: I combined 2 Dallas keepers in to one generic keeper since they each had significant minutes).

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Now, I guess it's possible that NYCFC's defenders just happen to give up a higher % of "easy" shots (so that even though they give up fewer shots, the ones they give up are from spots where Saunders couldn't possibly save it). But it could also just be that Saunders sucks at saving shots on goal (he's 19th in the league with a 59% save percentage) - and isn't that just a more fun explanation?

OK, the final piece of the puzzle is to understand what the impact is on our results. To check that, I assumed the same NYCFC possession/defense (the same shots allowed per minute), and just adjusted Saunders save percentage from his horrible 59% up to the league average 72% (not even great - just assume he was an AVERAGE keeper).

If Josh Saunders was an average keeper, NYCFC would've given up 8 goals so far instead of 12 goals. 4 fewer goals in 7 matches, or 0.6 goals per match. NYCFC scores 1.3 goals per match and allows 1.7 goals per match (net -0.4 per match). If we had an average keeper instead of Saunders, this would flip to 1.3 goals for and 1.1 goals against per match (net +0.2 per match).

(P.S. - What do you all think of a "Stats Central" thread for statistical fun like this? Just didn't seem to fit in anywhere else, and I like the idea of being able to find all this type of stuff in one spot.)
I Didn't bother to read the rest of your post . You had me with the first sentence!!