In my look at sabermetrics and hockey, I am looking at the problem of combining zone starts and Corsi Number. Although a method has been proposed by objective NHL, I have made my own which I think better solves the problem.
Raw Corsi Numbers are used as a metric to rank puck possession. Because teams are more likely to allow shots if they are in the defensive zone or take shots if they are in the offensive zone, individual player’s Corsi Numbers are adjusted by 0.8 * (defensive zone starts - offensive zone starts), as it has been shown that an extra zone start on average yields 0.8 shots directed at the goal.
When the San Jose Sharks lost in the first round of the 2009 playoffs many of their fans called for wholesale changes. The team had done increasingly better in the regular season for the last few years but had no significant playoff success. They won the 2009 President’s Trophy and were expected to do better than a first round playoff loss.
The urge was to trade away key players. Joe Thornton and Patrick Marleau were among the candidates to be shipped out of town. That would have been a bad idea for the Sharks. They were not going to get better by subtracting parts. They were highly unlikely to add better pieces in their place if they were trading away their best players.
I have written in the past about travel problems for the western teams, but it looks like things will be even worse than usual for the Western Canadian teams this year (Calgary, Edmonton and Vancouver). The US Government has banned Canadian charter flights from flying from point to point in the United States. This ruling is an attempt to protect American jobs. Typically, an NHL team has a contract with a particular airline (most likely Air Canada if it is a Canadian team) that they use for charter flights throughout the season. They are flown to all of their games and other events. Since teams often have extended road trips with multiple road games in the US, they often require flights between US cities. In the past an exemption to this law had existed for Canadian sports teams and entertainers traveling in the US.
The NHL has several markets that are in poor shape financially. The most prominent example is that of the Phoenix Coyotes, who are in bankruptcy. The team will be auctioned off very soon, with no clear end in sight to all the litigation and potential financial issues. The Tampa Bay Lightning are probably the NHL’s next serious problem. Owners Oren Koules and Len Barrie have barely had enough money to keep the team afloat. With Barrie apparently dropping out due to his financial difficulties, it leaves behind Oren Koules to run an underfunded team with declining fan support.
Yesterday, I wrote about the sabermetrics and hockey problem of combining zone starts and Corsi Number. There is as method used by objective NHL that treats Corsi Numbers as a rate statistic and adjusts by a factor similar to the percentage of offensive - defensive zone starts divided by total zone starts. I do not think this is the best method to treat this data.
I take the raw Corsi Number as a starting point. Since each extra offensive zone start is worth on average 0.8 Corsi (or each extra defensive zone start costs on average 0.8 Corsi), I merely add on a factor of 0.8 * (defensive - offensive zone starts). I think this method is more straight forward and better accomplishes the adjustment we are looking for.
In my sabermetrics and hockey posts this summer, I have introduced the concepts of the Corsi Number and of zone starts. Corsi Numbers measure the number of shots directed at goal (including shots on goal, missed shots and blocked shots) and zone starts measure which region on the ice that a player is in when he is on the ice for a faceoff. It should be clear that if you start frequently in the offensive zone that you should see a benefit in your Corsi Number as a result. Similarly, if you take a lot of faceoffs in your own zone, it should hurt your Corsi Number. This is one thing that can be adjusted for. In fact, objective NHL has done this.
The medal round of the Women’s Canada Cup has been played in Vancouver, British Columbia this weekend. For preliminary round results look here.
In the semi-finals, USA met Finland and Canada met Sweden. Here are the results:
USA 4 Finland 0 This was a re-match of the only preliminary round game that USA lost. This time they had a better game. Meghan Duggan scored a hat trick for the US team, with Gigi Marvin assisting on each of the goals. Jocelyne Lamoureux added the other US goal. Jessie Vetter stopped 19 Finland shots for a shutout. Noora Ratty was in goal for Finland.
Canada 7 Sweden 2 The outcome of this game was never really in question. Canada took a 6-0 lead into the dressing room at the end of the second period. Emotions got a little out of control and a couple near brawls occurred. In the third period, Sweden managed to get on the scoreboard but it was too little too late. Hayley Wickenheiser and Sarah Vaillancourt each scored two goals for Canada. Kim St Pierre was the winning Canadian goalie. Isabelle Jordansson and Danileja Rundqvist scored the Swedish goals. Sara Grahn was in goal for the losing Swedish effort.
The women’s Canada Cup hockey tournament is underway. It is being played in Vancouver. Four teams are playing: Canada, Finland, Sweden and USA. The preliminary round is now over. Here are the results:
1. Canada 2 wins 1 loss 19 goals for 6 against. Canada easily beat Finland and Sweden with 10-2 and 7-0 scores respectively and then lost to the Americans in 4-2 game. Canada’s balanced attack featured strong performances from Rebecca Johnston, Haley Irwin, Hayley Wickenheiser and Caroline Ouellette. In goal they used Kim St Pierre and Shannon Szabados, who were not tested much until the USA game.
2. USA 2 wins 1 loss 13 goals for 6 against. USA managed to defeat Canada, but they had lost earlier to Finland. The US attack was led by Hillary Knight with five points and Caitlin Cahow and Natalie Darwitz who each added four. Molly Schaus took over the US nets after the Finland loss and has played very well.
3. Finland 1 win 2 losses 6 goals for 15 against. Finland’s success was their opening day 3-2 upset against USA. They have not won since. Their offence has been led by Saara Tuominen and Michelle Karvinen, each have 3 points. Noora Ratty has been their top goalie. She stole the game against USA, while being outshot 51-23.
In my most recent sabermetrics and hockey posts I have been discussing the Fenwick Number. It is essentially a measure of puck possession that measures all 5 on 5 shots on goal and missed shots for and against when a given player is on the ice. It is much like the Corsi Number. Both Fenwick and Corsi Numbers are attempts to find a replacement for +/- ratings that will include more events and thus have higher signal to noise. I have listed the players with the top 20 and worst 20 Fenwick Numbers as well as listing the team Fenwick Numbers.
Today I will address the question of whether the Fenwick or the Corsi Number better correlates with winning.
A lot has been written this summer about the bankruptcy of the Phoenix Coyotes and its aftermath. Phoenix is not the only team with financial difficulties. It is a very reasonable expectation that the Tampa Bay Lightning could follow them down that path in the near future. As we have learned from the Phoenix bankruptcy, the NHL will attempt to hide and deny problems for as long as possible (they are probably doing so already).
Here is the case that something is amiss in Tampa Bay. The OK Hockey Group (Oren Koules, Len Barrie and some other minor investors) bought the Tampa Bay Lightning in 2008. They could not afford to buy the team through normal means and required former owner Bill Davidson to extend financing for the purchase. Davidson has died since the purchase, but his heirs remain major creditors to the Lightning and could use their leverage to attempt to take control of the team, if they decided that was in their best interests.
About The Puck Stops Here
Who am I? A diehard hockey fan.
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