they have basically taken a stat like fenwick which actually has a fairly weak correlation with future wins, and are treating it as if it is a much stronger predictor than it actually is. It's correlation with future wins isn't strong enough to suggest its a a clear "cause" separated from all significant "effects", yet they still treat it as if the numbers have shown that we can actual model predictions with fenwick as the "reality", and factors such as sh% and sv% as just luck or small sample variation factors.
fenwick and corsi are nice stats that tell us something, but the conclusions being drawn from them are far too strong to be justified.
and this year is ESPECIALLY glaring because they are insanely drawing these conclusions from a the tiny half-season sample we had last year. even a full season is a small sample for the advanced stats with a weak correlation to future wins - a half-season sample is even weaker by orders of magnitude.
to give a layman's example, let's look at, say, Bozak.
Bozak Career:
Career: .23gpg, .56ppg
12/13: .26ppg, .61ppg
11/12: .25ppg, .64ppg
10/11: .18gpg, .39ppg
09/10: .22ppg, .73ppg
What we see there is a fairly consistent producer over his career. A guy with a hot rookie year, a bit of a sophomore slump, who then settled in between there the next two years, just a tad above his career average.
We have a solid track record to work off of here, which would give us very good reason to predict him to come in again around .25ppg/.60ppg level this year.
But an "Analytics Guy" is not allowed to draw this fairly simple conclusion, because last year Bozak had a 19.7sh%, an 11.1on-ice sh%, and a 1027 pdo. The "analytics guy" will be forced to claim that Bozak is very likely to suffer significant regression this year from last year's production - despite the fact that that would mean Bozak would "regress" to a level well below his relatively consistent career norms - career norms that were established before last year, even with less "lucky" advanced statistics.
So for an Analytics Guy, Bozak overachieved last year and is due for regression this year - even though Bozak simply continued on scoring at his typical career level last year.
And in fact, when you actually look at all the leafs' career production, weighted for recentness and adjusted for minutes played, it's very hard to argue that many leafs overachieved offensively last year, despite what the advanced stats say. About the only two leafs who played a significant amount of games that could legitimately be said to overachieve were kadri and franson - but even then, those were young guys gettting their first legit offensive opportunities, so their lack of track record is hard to hold against them. And moreover, a number of players, either due to poor performance or injury, clearly underachieved last year to balance those guys out - Lupul, Grabo, gardiner in particular.
What we've ended up with is having so many people with a fairly poor understanding of statistics, who have developed unjustified tunnel vision when it comes to these possession stats - they have literally convinced themselves that last year's half-season sample of possession stats has to be the "base" of their analysis, and are actually completely disregarding contrary facts like the Bozak example I showed above. For them, it doesn't matter that Bozak scored at his usual rate last year - he has to be due regression, because the advanced stats from a half-season sample size say that he was lucky last year.
They're making a big mistake, IMO.
But hey, maybe I'm wrong.
