May 012013
 

I brought this issue up on twitter today because it got me thinking. Many hockey analytics dismiss face off winning % as a skill that has much value but many of the same people also claim that zone starts can have a significant impact on a players statistics. I haven’t really delved into the statistics to investigate this, but here is what I am wondering.  Consider the following two players:

Player 1: Team wins 50% of face offs when he is on the ice and he starts in the offensive zone 55% of the time.

Player 2: Team wins 55% of face offs when he is on the ice but he has neutral zone starts.

Given 1000 zone face offs the following will occur:

Player 1 Player 2
Win Faceoff in OZone 275 275
Lose Faceoff in Ozone 275 225
Win Faceoff in DZone 225 275
Lose Faceoff in Dzone 225 225

Both of these players will win the same number of offensive zone face offs and lose the same number of defensive zone face offs which are the situations that intuitively should have the greatest impacts on a players statistcs. So, if Player 1 is going to be more significantly impacted by his zone starts than player 2 is impacted by his face off win % losing face offs in the offensive zone must still have a significant positive impact on the players statistics and winning face offs in the defensive zone must must still have a significant negative impact on the players statistics. If this is not the case then being able to win face offs should be more or less equivalent in importance to zone starts (and this is without considering any benefit of winning neutral zone face offs).

Now, I realize that there is a greater variance in zone start deployment than face off winning percentage, but if a 55% face off percentage is roughly equal to a 55% offensive zone start deployment and a 55% face off win% has a relatively little impact on a players statistics then a 70% zone start deployment would have a relatively little impact on the players statistics times four which is still probably relatively little.

I hope to be able to investigate this further but on the surface it seems that if face off win% is of relatively little importance it is supporting of my claim that zone starts have relatively little impact on a players statistics.

 

  5 Responses to “Face offs and zone starts, is one more important than the other?”

  1.  

    Maybe, i am missing your point (it might be over my head), but losing faceoffs in the O-zone can’t have a positive impact in his statistics. If Player A loses more draws in the offensize zone, than his line will generate less shot attempts and will let up more shot attempts (compared to a player than loses less offensive draws). Same goes for D-zone. A player who wins a lot of Defensive zone draws (percentage wise) will give up less shot attempts and generate more shots on goal because his team has the puck. This seems very simple to me, which leads me to believe that I’m not understanding your point.

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      Well, the question really is, does losing face offs in the offensive zone have a significant advantage over winning face offs in the defensive zone because in the player 1 vs player 2 scenario above, that is where the difference lies.

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        Well player 2’s zone starts will be worse off than Player 1. Player 2 in this scenario as a 50% zone start compared to 55% zone start for player 1. So already we know that Player 2 plays tougher minutes (just based on zone starts alone). That should help tell us something about those two players in comparison to each other.

        Now in this scenario let’s assume that Player 1 and Player 2 play the exact same competition, play with very similar line mates, and are of equal skill. We could assume that Player 1 and Player 2 will give up the same amount of shots, scoring chances, and/or goals per face off loss in the defensive zone, since both players lose 225 draws. In the same token, the same amount of shots, scoring chances, and goals will be generated by the lines of Players 1 and 2 per face off win in the offensive zone, and both players win 275 offensive draws.

        So the potential difference between the two players (in terms of shots generated, goals, Corsi, etc) is how losing 275 draws in the offensive zone compares with winning 275 defensive draws in the defensive zone.

        We could figure this out by taking all shifts in the NHL that started with a face-off loss in the offensive zone and determine the results of such plays (whether it be in Corsi, Fenwick, shot differential, etc). I think it would be best if we put that in terms of Corsi/fenwick/shots generated per face off lost in offensive zone. We should do this for all shifts, grouping them by zone they started in and result of the face off. We could get an average for each situation for Corsi generated per face off.

        Then we could find how many shots/corsi/fenwick were lost by losing those face offs in the offensive zone and how many shots/corsi/fenwick were prevented by winning those defensive face offs. Thus, we could determine the value of those lost and won face offs and accurately attribute the value gained/lost by each player. Of course, Player 1 is an average face off man (50%) so his techniqually he has neither positive or negative value in the face off circle. However, Player 2 does bring value because he helps generate shots and shot attempts by giving his team possession more often than not on offensive draws and he helps prevent shots and shot attempts by giving his team possession more often than not on defensive draws.

        I hope I’m making sense here. There would have to be adjustments in the calculation for score adjustments, and also there would have to be a time limit (I believe you have mentioned the 10 second rule for zone starts) where any shots generated after those 10 seconds would not be taken into account for face offs.

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          Yeah, you are making sense and I believe some of this work has been done. I brought this up because some people believe 1) Zone starts have a significant impact on a players stats and 2) Winning face offs do not have a major impact on a players stats.

          I am questioning how that can be the case. You present a method to dig into finding the answer.

          •  

            I’d do some of that digging myself but I don’t really know how to go about collecting all that data and analyzing it without advanced software. I am relatively new to the world of advanced statistics in hockey (I’m only 17) so the only thing I could do would be to plug everything into excell and then work from there (which I’m guessing would take alot of time), plus I’m not really sure how to find some of that info. I’d really love to get involved deeper but not sure how most people like yourself collect and analyze all this data unless you guys have and know how to use software programs that help with this.

            I’d say to anyone that doesn’t give value to face-offs wins that they are misguided. Everything that I have read in the advanced metric community focuses on puck possession. We have a few stats (shots, missed shots, blocks) that enable us to roughly calculate how a player, line, or team controls the play. Because face-offs immediately give one team possession of the puck over the other, the face off win contributes to puck possession (which in the end contributes to eventual goals).

            Take Kunitz and dupuis for example. Clearly Crosby elevates their Corsi ratings tremendously (and we have certain metrics like Rel Corsi that partially account for that). But he eleveates their ratings not only because he is one of the best players in the NHL that can keep puck possession and create shot attempts, but he also is a good face off man. More often than not he wins the puck back to his line mates, thus giving them possession and giving them the opportunity to generate shot attempts.

            While the success of the Crosby line cannot be solely attributed to Crosby (Kunitz and Dupuis also help keep puck possession and generate shots), the fact that Crosby gets his team the puck more often than not on face offs can ONLY be attributed to Crosby.

            This is in my opinion the beauty about hockey analytics. With every day hopefully we can come closer to finding the true value of players and the true value of individual plays.

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