Garret: Evaluating 2way players... Please judge me
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11-21-2012, 05:02 AM
Join Date: Mar 2012
Originally Posted by
Garret? Is there a tutorial for those kind of stats or something like that? I don't understand at least half of them.
Sure thing. I'll give a lil' breakdown but link to Gabriel Desjardins FAQs on advance statistics. Desjardins is a man originally from Winnipeg who runs behindthenet.com (the website where most advance stats guys gets their data) and has worked for as a consultant to multiple sports networks and NHL teams. He also founded Arctic Ice Hockey.
Part 1 - Plus/Minus statistics
I think every fan in hockey understands basic plus/minus; it's just a goal differential of when you're on the ice. There are more advanced plus/minus' and that's what Gabe talks in the link, but I usually don't use those because they can be affected by goalies and luck too much.
So plus/minus is the goals going on when you are on the ice. We all know this but Corsi is related so I wanted to review.
Part 3 - Corsi Number
Plus/minus is a goal differential, while Corsi is a shot differential (usually includes missed shots and blocked shots). As I noted above plus/minus is affected by the goalies on either side, the shooters percision and luck; what Corsi does is remove a lot of that noise, so the differential better correlates to who is outplaying who. Corsi is named after a Buffalo Sabres' goalie coach, Jim Corsi, who invented it. So basically, think of it as plus/minus but includes shots, goals, blocked shots and near misses. Also, we don't use raw whole numbers, but divide so the value equals the amount per 60 minutes of icetime. That way when you compare a 4th liner to a 1st liner, it evens out the difference from additional ice time. We usually do that with all stats. Corsi, like plus/minus, is positive when you are outshooting your opponent, and negative when you are being outshot.
Relative Corsi (RelCorsi) is a players Corsi relative to the teams average. This is the best for when compairing players on different teams since it removes the factors of playing on a really good or really bad team.
Part 2 - Quality of Competition
Quality of Competition (QoC) is what it sounds like. It's a measurement to determine whether or not you faced against the other teams top line, 4th line, or anywhere in between. In Gabe's writeup he uses a variation of plus/minus of the opponents the player lines up against to calculate their QoC. Nowadays (the article was written 5 years ago) we use the opponents Corsi. So basically all QoC are averages of a stat of your opponents you are on the ice against, but weighted for the amount of time you play against them. So 1 min against a topline and 2 mins against the 4th line is lower Qoc than 2 mins against a topline and 1 min against the 4th line. A larger (more positive) QoC means you mostly faced top lines, a smaller (more negative) QoC means you mostly faced 4th liners.
QoC (or CorsiQoC) is the avg Corsi of the opponents he faces, weighted to the time they play against each other.
RelCorsiQoC (or RelQoC) is the same thing but uses RelCorsi instead of Corsi. This is always better for determining usage IMHO.
Part 4 - Zone Starts (or Offensive/Defensive Zone Faceoff Ratio)
Offensive Zone Starts (OZS) is a measurement of the amount of times the coach puts you on the ice for a faceoff in the offensive zone, or the other teams defensive zone. This is used a lot to determine usage. Coaches tend to give their scorers mostly OZS while their more defensive players DZS (defensive zone starts). Combined with RelQoC this gives a good idea of a persons workload when it comes to scoring or Corsi. A person who usually starts in the DZone will have more trouble scoring than a person who usually starts in the OZone.
OZS% shows what percentage are you starting in the OZ relative to OZ + DZ starts. We don't include neutral zone starts in the calculations.
OZF% shows what percentage of your shifts end in the OZ... but it tends to not correlate as well with skill or usage. I was fiddling with using it as a skill determiner above, which was what I was asking about.
Part 5 - Penalty +/- (or Penalty Differntial)
Just another differential. This one is how many penalties you draw vs how many you take. Some players take more penalties than others. Some players draw penalties from other teams by being a pest or by being so skilled/fast that the other team consistently screws up and has to hook/slash. PPs are good and PKs are bad, so we look at the differential of these to determine if you are helping the team or hurting the team with your ability to draw and make penalties.
Part 7 - Goals and Points per 60 Minutes
As I mentioned before, we tend to make stats per 60 minutes of ice time. The reason for this is I may have more goals than you, but it may be because coach gives me more icetime, not because I score faster or better than you. We tend to seperate primary and secondary assists because secondary assits tend to fluctuate for a player hugely throughout a carreer and isn't a good indicator of skill (this is more true for forwards than dmen).
G/60 - goals per 60, A1/60 - primary assists per 60, pts/60 (or p/60) points per 60
There are other stats, but I have yet to use any of them...
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