Shootout Math: Applications of QualCLUTCH

Cam Charron
February 09 2012 07:18AM


Alex Edler upsets the ladies with his shootout prowess.

You've probably noticed but four of the last five games the Vancouver Canucks have played have been settled in a shootout. This isn't necessarily horrible, at least the home team has been picking up points. They're also giving us more to fret about over the last week or so than any discussion about obnoxious tie games and how they're ruining hockey, so there's that too.

Somehow, out of this mess, the Canucks have emerged as one of the top shootout teams, winning three of their last four and bringing their record up to 5-5 in the skill competition, on the season. So what have we learned from this?

  1. Roberto Luongo may not be as bad as he seems at this.
  2. Alexander Edler is actually pretty good.
  3. It doesn't really matter one way or the other.

But, again, these things are fun to discuss. For instance, if we know who our best shooters are, when do we send them out? First, second or third? I sent an email off to a mathemagician friend of mine, the pride of Burlington ON Rob Pettapiece, who runs the CIS Blog and, with a math degree from Waterloo, takes a keen interest in the numbers side of sports. I think I was discussing Corsi and Fenwick with him before he even learned the rules of hockey.

So we had a nice email exchange about shootout situations and since Rob has done work in the past that looked at win expectancy for every state of a volleyball game, I was wondering if he could do it for a simpler hockey shooter. This was centred around the basic question "At any given moment in a shootout, how likely are you to win?" Rob went out creating a model that addressed all 15 possible states of a shootout (ie: which team is shooting, what's the score, and what round).

From that link, there's a spreadsheet view of each probability. For instance, when the first shooter goes, for example, Mason Raymond on Tuesday in Nashville, his team has a 50% chance of winning. When Raymond missed the net on his first attempt, the Canucks' chances of winning dipped to 38%. Had they scored, the chances would have increased to 70%. Here's a nice graph:

You see 13 game states below, with the blue line representing the likelihood of Canuck victory at any moment during the shootout:

  1. The shootout starts. Both teams have an identical 50% chance of winning.
  2. Mason Raymond MISS - Canucks chances drop to 38%.
  3. Sergei Kostitsyn SAVE - Canucks chances are back up to 50%.
  4. Ryan Kesler SAVE - Down to 36%
  5. Martin Erat MISS - Back up to 50%
  6. Alex Burrows GOAL - Canucks chances climb to 82%.
  7. David Legwand GOAL - Back down to 50%
  8. Daniel Sedin MISS - 32% (see a pattern?)
  9. Mike Fisher SAVE - 50% (there it is)
  10. Cody Hodgson MISS - 32%
  11. Ryan Ellis SAVE - 50%
  12. Alexander Edler GOAL - 82%
  13. Colin Wilson MISS - 100%

After all 13 states have played out, the Canucks' chances of victory were at 100%, giving them the extra point against Nashville. The reason why the percentage swings more in some states is because of how much "time" is left for the first team to catch up. The Raymond miss in State 2 didn't affect the team as much as Hodgson's miss in State 10, because the Canucks still had at least one guaranteed shot ahead.

Two pertinent questions were answered here. One is that it doesn't matter what order you send your top players out, so long as they are in Rounds 1 or 2 and thus guaranteed a shot. The "leverage index", which calculates the importance of each shot (Round 3 has more leverage on the outcome than Round 1) is always equal to 1 in Round 1, and averages out to 1 in Round 2. Without knowing what the score will be after the first round, you're pretty much flipping a coin to determine whether you should send your best shooter out first or second. 

The second question is what order the teams play in. Since the leverage indices average out, it really doesn't matter whether a team goes first or second. Writes Rob:

This isn’t baseball, where batting last gives you an advantage because you know how many runs you need to win. (The baseball analogy would be a home-run derby, with one pitch to one batter from either team until someone wins, which aside from being stupid would not confer any advantage on the first or second team. Of course, if the NHL ran MLB, they’d probably institute that right away.)

Win expectancy graphs are famed in baseball, where they not only tell which team is close to victory and their odds, but also add up how much each player tilted the graph. For instance, a player who brings his team's chances of winning from 50% to 60% would have a .10 wPA, or "win probability added" which has very little tangible use, but is good for telling a story. Players with high wPA's are often the "clutch" hitters that win games, or are lucky enough to come up to bat in important situations.

So I decided to do the same thing for the Canucks in shootouts. I looked at all 10 shootouts and added up which Canucks tilted the percentages in their team's favour. The results were unsurprising:

Player wPA aLI
Edler 40% 1.19
Schneider 38% 1.06
Burrows 31% 0.90
Raymond 5% 0.95
Luongo -2% 1.11
Hodgson -3% 1.20
Bieksa -12% 1.00
Lapierre -12% 1.00
Samuelsson -12% 1.00
D. Sedin -18% 1.56
Kesler -55% 1.17

wPA refers to the "win probability added" statistic I just talked about. aLI, or "average leverage index" refers to the average situation a player faced: anything over 1 is a "clutch" situation and a lot of opportunity to swing your wPA one way or another. 1.19 is the highest leverage possible in the second round, with 1.56 being the highest in the third round. You can see the kind of situations that Alain Vigneault likes to confer upon Cody Hodgson. Both of his goals were deciding goals.

Ryan Kesler, who is 1-for-4 on the season, had the misfortune of scoring his only goal when the Canucks were up already in the shootout (against Montreal). This meant his goal had little impact on the result of the game, while his three misses came in high-leverage situations. He has the lowest shootout QualCLUTCH on the team.

Alex Edler, as noted earlier, is quite good at this, and I'd wager he's the best on the Canucks. He didn't go until Round 6 against Nashville after being the first shooter in his two other attempts. He's 2-for-3 on the season and 4-for-12 on his career. While the league average for shootouts is 37%, the Canucks don't have many players who can score at that clip in the shootout (Andrew Ebbett, Alex Burrows and Maxim Lapierre, with Ebbett and Lapierre only having 9 attempts between them). In light of the overall struggles of the team's shooters in the skill-competition, anybody who pots a third of their attempts is okay in my book.

So from this, Vigneault is probably better off using Edler and Burrows as his first and second shooters. From then on, he may as well be picking names out of a hat. Cody Hodgson is a good option (unless you think his wPA means he'll come up short in important situations, although that's more of an effect of Cody being sent out often in those tough situations), and Raymond is a fine selection too. With Kesler, David Booth and Daniel Sedin, you're running into guys who shoot below the replacement-level of about 30%, so Vigneault may as well use Keith Ballard, Henrik Sedin, Manny Malhotra or Jannik Hansen.

Speaking of which, why hasn't Jannik Hansen gone this year? The Canucks have had 29 shootout attempts this season, and Hansen hasn't come over the boards for any of them.

wPA may have limited practical application, but it's a fun thing to look at, particularly when comparing goaltenders. Luongo is still hurting more than helping his team, as his 18 saves have come at the wrong time compared to his 12 goals against, which doesn't really help the perception of a goalie who is "mentally weak" and "can't come up big." Then again, he's at 86% in his last two games, having stopped 8 of his last 9, so I think that he's experiencing some regression to the mean in his recent performance.

Either way, as the Canucks continue to pile up shootouts, the numbers become more fun to discuss in more different ways. Rob's post is a great tool for learning more about the shootout, and, as a numbers guy, he has a lot of other tools for the stray sports fan, probably being best known for his CFL third-down study which proved football teams should go for it more. If you're into baseball and humour, he also ran a study investigating players who claimed to be in "the best shape of my life" prior to spring training. And, from the seems-obvious-but-no-teams-have-realized-this files, his famous post about teenagers aging , even hockey players.

For more on win expectancy in hockey, there was a terrific post at Arctic Ice Hockey that looked at a team's expected point total by game state . There is really some awesome research being done on individual player's impact on games.

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Cam Charron is a BC hockey fan that writes about hockey on many different websites including this one.
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#1 John Andress
February 09 2012, 12:11PM
Trash it!
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props

I love these statistical views of the game and game situations. Not being mathematically adept I cannot say in all honesty that I understand them all but they do make me realize that there is so much, much more depth and substance to the game that I already loved than I had ever imagined. Keep them coming and I will try to keep up.

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#2 J21
February 09 2012, 02:05PM
Trash it!
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trashes
+1
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props

Even in his limited body of work, Hodgson has looked more dangerous to me than Raymond (including hitting the post last game), and I wouldn't be surprised if he ends up as the highest percentage shooter if Vigneault gives him the chance.

I think Kesler would have a much better percentage if he played the shootout like he does a game and just shot from farther out.

The idea of not putting your best shooter 3rd -- in a position where he may not be able to go -- is very intuitive even without a study, though. I don't know what the Canucks are thinking when they reserve Burrows for that still-hypothetical shot. It's like saving your stronger fighters in a war until the enemy has killed all your weaker guys.

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