The Caps by Zone Differential

The boys over at The Copper & Blue created a stat called Zone Differential, based on their work with Expected Zone Finish; basically, it measures the expected ratio of times a player ends on an O-zone stoppage as opposed to the actual ratio. Our inestimable leader J.P. did something similar way back in January of '09, although the calculation is a bit different.

More explanation and tables after the jump and as always, all numbers from Behind the Net and the NHL website.

So the idea behind Zone Differential is this: It's the difference between a player's actual percentage of offensive versus defensive zone finishes. Offensive Zone Finish Percentage is calculated via this formula:

OZF/(OZF + DZF) = OZF %

where OZF is the number of Offensive Zone Finishes and DZF is the number of Defensive Zone Finishes. I've credited each player with an additional OZF for every goal that was scored by the Capitals while they were on the ice and an additional DZF for each goal that was scored against the Caps while they were on the ice (h/t to J.P. for that adjustment method).

If you click the link on Expected Zone Finish % before the jump, you'll find that C'n'B used the formula:

OZS% - .7(50-OZS%) = Expected OZF %.

The chart used in the link (really worth looking at) makes this regression factor look pretty good; I'm going to run with it for now. OZS is the % of times the player started in the offensive zone instead of the defensive zone, calculated in the same way that OZF is. The idea behind that regression is that if a player starts more often in one zone than the other, he's got a better chance to head in the opposite direction; The best a player can do on an offensive zone start is an offensive zone finish, he can't move any further forward. Similarly, we'd expect players that start in the D Zone a lot to move towards the 50% marker on the finishes, because they have a better chance to move the puck forward. The puck does a lot of heading into the neutral zone, for whatever reason.

This method certainly has shortcomings; moving from the defensive zone to the neutral zone is certainly valuable, but it's not captured here. It's also totally unadjusted for quality of competition and quality of team. I've included Corsi Qual Comp in the table as a reference point, but that's somewhat confounded with Zone Start: every offensive zone start is worth, according to this work by JLikens (h/t Derek Zona for digging it up), a net of +.8 positive Corsi events. The upshoot of that is guys who get a lot of O-Zone starts read as tougher competition than they actually are and guys who spend a lot of time starting in their own zone have worse Corsi numbers, both in relation to their team and on the absolute scale, meaning they get knocked down a peg in terms of their QualComp ratings.

However, as my signature says, "all models are flawed, but some are useful". I think this one is fairly useful to see which players are taking the puck in the right direction and which players are getting pushed back.

Without further ado, here's the table, sorted by Zone Differential.

There are some really interesting nuggets in this data:

Firstly, something we already knew; Alex Ovechkin is the best player on the team and by a pretty wide margin.

Tom Poti and Eric Fehr both rate very highly on this metric. Both of them rated very highly in J.P.'s zone +/- rating, so this shouldn't come as a huge surprise. What is surprising is that Poti is used as the team's defensive stopper, getting the smallest percentage of OZS out of all defenders and faced the highest Corsi QComp, yet he still moved up the ice better than any of the rest of our D-Corps. Poti may not be all washed up, after all.

Fehr continues to shine in just about every ratio and per-60 metric, despite getting very limited use by HCBB. Last year, I was willing to chalk that up to playing with Sergei Fedorov, who was a Corsi and defensive beast by the numbers, but he's had no such advantages this season. I'm not sure how he does it, but F-16 gets results.

Jason Chimera gets up the ice like a demon -- not all fast players can do this, but Chimera certainly can. In Columbus, this was recognized; Hitchcock used him a lot in the defensive zone to move the puck out of the defensive zone. That (along with no PP time to speak of) put a damper on his scoring, but I like his value on his current contract.

Steckel, ouch. I really hope 39 can turn this around; he got demolished last year. He's got to work on either his skating or his ability to pass out of bad situations. Something, anything, to get those numbers turned around.

Shaone Morrisonn -- I'm glad you're in Buffalo, now. His underlying numbers are brutal, especially considering how much time he spent with Mike Green near the beginning of the season. I'd bet good money that during the 2008-9 season, Green was doing what he did at evens in spite of Morrisonn, not because they worked all that well together. That season gets more impressive every time I look at it.

Speaking of Green, he doesn't do all that well by this metric, especially by comparison with Schultz and Poti. I'm very interested in what this season holds for @GreenLife52; can he recapture the play that put him on the Norris map, or does he continue on his course as an offensive defender without peer, but one prone to serious brainfarts and bad turnovers.

It's also worth noting that Bradley and Walker stand head and shoulders above their 4th line mates. This fits with most of the other data I can dig up; Brads looks like one of the better 4th line grinders in the league and Walker looks like he was underused, both in WSH and CAR.

Belanger's alleged new contract doesn't look so good when you look at this, his Corsi at evens and his PK stats; I'm not convinced that he's getting by on anything but reputation in the role he's currently playing. We'll (maybe) see if he improves this season, but ouch. I'd much rather have Jeff Halpern for the same money and the same role.

This method mostly passes the sniff test, but also yields some fairly surprising results. I'm curious to hear what y'all think down in the comments.