Custance: NHL stars suspicious of latest data on ideal time to pull the goalie
By Craig Custance Sep 21, 2018
Anders Lee forgets exactly what the class was called. Some sort of business management statistics class at Notre Dame. But the Islanders forward definitely remembers one of the projects.
The class tried to use statistics to determine the optimal time during a game to pull the goalie and the results were aggressive. Certainly much more aggressive than the current hockey standard, where coaches typically wait until around the 90-second mark to add the extra attacker.
Lee remembers sitting in the class with a couple of his hockey-playing teammates and shaking his head when the conclusion suggested that coaches should start thinking about pulling their goalie with at least three minutes remaining in the game. In his mind, this was an exercise destined to stay in the spreadsheets.
So when this topic came up again a couple weeks ago, Lee was ready for it. This summer, on his excellent podcast “Revisionist History,” Malcolm Gladwell shared the work of two Connecticut math geniuses — Clifford Asness and Aaron Brown — who took on this same topic in a 13-page paper posted on research website SSRN titled Pulling the Goalie: Hockey and Investment Implications. This isn’t new ground in the world of hockey analytics, but their results were even more aggressive than some published previously. Certainly more than Lee’s class exercise.
In setting up the results on his podcast, Gladwell sums up where hockey is in embracing data like this compared to other sports.
“Baseball is quantum theory,” Gladwell says. “Hockey is the grown-up professional version of ‘Red rover, red rover, let Wayne Gretzky come over.’"
This may just be most evident in the strategy of pulling the goalie. Goalies are typically pulled around the 1:30 mark, not because of any data that suggests that’s the ideal time. Mostly, because that’s how it’s always been done, the exact phrase that tends to keep hockey in the Red Rover era. When Patrick Roy started to change things on this front and aggressively pulled the goalie as coach of the Avalanche, it wasn’t because he studied the numbers. It was because he’s Patrick Roy and he’s full of swagger and in his gut, he thought it was the right thing to do.
“I never look at the statistics, to be quite honest,” Roy said when we asked about it in 2014. “I think sometimes — just go with the feelings.”
If this latest work on the topic by Asness and Brown is accurate, those feelings were spot on. And the conclusions of Lee’s class at Notre Dame? They might have even been a bit conservative.
“I want to see how close it is,” Lee said when presented the new data.
Lee was handed a pad of paper with the conclusions of the report summed up on three lines. The ideal strategy, according to Asness and Brown:
Teams that are down one goal in the third period should pull the goalie with 5:40 remaining. Teams that are down two goals in the third period should pull the goalie with 11:40 remaining. Teams that are down three goals in the third period should pull the goalie with 17:40 remaining.
It gets even more aggressive.
If you’re down four goals? The optimal time to pull the goalie is with 35:50 remaining in the game. Once you’re down five goals, it’s open season. Do it at the first opportunity. You can check the math here.
“I’d be pissed,” Lee said, while examining the numbers. “I’d be pissed off. It’s almost a guaranteed minus. … If it’s the end of the game, I don’t mind the minus. You’re trying to tie it up. Here’s the deal — with 17 minutes left and you’re down three, I look at it as getting a goal every five minutes. You have plenty of time.”
And the authors of the paper conceded that this strategy would lead to lopsided results. Games would get out of hand. Fans might be upset about lopsided scores. Coaches would face heat.
But they remind us that the number in the standings column that counts most isn’t the goal differential, it’s total points. According to their paper, the NHL coach who implements this strategy will add 1.76 points to their team’s total over the course of the season. In a league filled with parity, that would definitely push some team into a playoff spot that might not otherwise get there.
From the paper:
“The point of hockey is not to maximize the differential between the goals your team scores during the season and the goals it gives up (if it were, no one should ever pull a goalie). The point of hockey is to maximize the number of standing points — a team down by a goal with short time remaining gains a lot by scoring, and loses little if the other team scores — which argues for a different measure of risk and return. As we have shown, pulling the goalie actually reduces the risk of losing the game — it’s an insurance move — and this is the proper risk measure.”
They list a couple main reasons as to why this strategy isn’t adopted. For one, they see more reward for coaches who are perceived as good coaches as opposed to coaches who actually win. Keeping games close, even if it ends in a loss, adds to the perception that a coach is good at his job. A string of blowouts over the course of the season wouldn’t. They also contend that winning ugly is undervalued “versus losing elegantly.”
“If you lost 15 games with them scoring empty net goals, the media would be all on us because we’re giving up too many goals,” Wild coach Bruce Boudreau told The Athletic when presented this data.
Boudreau also suggested that playing an entire third period without a goalie and an extra attacker would mean coaches wouldn’t be able to reserve the ice time for the best offensive players, as they do now when a goalie is pulled. So you’d see the fourth line out there in a 6-on-5 scenario.
“It’s hard to pull your goalie and put your third and fourth lines out,” said Boudreau. “You really would look like you’re not playing to win at that point.”
There’s one other point not mentioned. The coach who implements this might face a revolt from the players. One NHL coach said he once pulled a goalie much more aggressively than usual and one of the team leaders turned back and yelled, “What the hell are you doing?”
Presented with this data, many NHL stars had the same reaction.
“It’s too early,” Blackhawks winger Patrick Kane told The Athletic. “The other team scores and it’s pretty much game over. You might as well give yourself a couple more shifts and maybe try to score one 5-on-5 and see what happens in the last minutes and a half. If you give one up at that point, then so be it.”
“It’s like in poker. If you just keep going all-in, every hand, every hand, eventually you’re going to lose and you’ll have absolutely nothing. That’s how I view that,” Hart Trophy winner Taylor Hall told The Athletic. “I think you have to wait. But if they have facts to back it up and numbers — I respect the numbers.”
“I can’t see how that works,” said Hart runner-up Nathan MacKinnon. “Do you agree with it?”
I mean, it’s math.
“One shot ends the whole thing,” MacKinnon countered, still not quite convinced.
MacKinnon did say it was fun to play for Roy when he was aggressively pulling goalies in Colorado. He remembers a time when the Avs were down three and Roy sent out an extra attacker with nine minutes left.
“It was wild. We actually would score a couple sometimes and it was, ‘Oh my God, we might come back here,’” MacKinnon said. “He was aggressive. He would be all over this.”
To get a goalie’s perspective, we turn to Marc-Andre Fleury. What would he say to Gerard Gallant if Gallant told him this was the Golden Knights’ plan heading into this season?
“‘Well, can we discuss?’” Fleury answered, laughing. “Hockey, it can turn around so quick. You don’t need 17 minutes to score three goals. I think if you get scored on, you’re down four and you’re not coming back. Wait and see how it goes and try to get a little closer.”
The numbers weren’t met with complete disagreement.
Stars center Tyler Seguin seemed lukewarm to the idea, but you got the sense you could talk him into it.
“Wow,” he said when given the data. “I’m a fan of pulling ‘em early. That’s a little aggressive. Four minutes I would be OK with, anything higher than that would be tough.”
Auston Matthews was a little warmer and if there’s a team that might one day implement this, it’s one run by Kyle Dubas.
“If you think about it, it’s not bad. Let’s say you’re down by one and typically you’re pulling it around two. A lot of times you end up still in their zone trying to score — imagine if you add two more minutes to that,” Matthews told The Athletic. “It kind of makes sense.”
To a point.
“Down by three — 17:40? I think I’m giving it some time,” Matthews said. “Maybe the boys put one in 5-on-5, 5-on-4. Down by one, that makes the most sense around that five-minute mark. Man advantage, typically the puck is in their zone, a lot of times you run out of time. I kind of like that.”
And then there was Claude Giroux. He’s all in on the idea, although he thinks there should be some strategy involved. Try to find an offensive zone faceoff following an icing to be ideal. But the aggressive strategy appealed to his offensive instincts.
“I would love it, to be honest,” Giroux told The Athletic. “It’s definitely smart.”
As a player with a former goalie as the GM, Giroux only sees one hitch.
“I like that,” he said. “I don’t see Ron Hextall liking that though.”
Don’t hold your breath waiting for an NHL coach to adopt this game plan in the coming season. But if other sports are any indication, it’s going to happen one day. And chances are, something similar is the correct strategy. Just like shooting threes in basketball and the shift in baseball.
It might not happen until these stars are out of the league but hockey will get there. At least that’s the assumption from the paper:
“It can take decades, but things do move in the rational direction. When this happens it proves that the stats geeks were right all along, but, more importantly, it also shows that it is possible to surmount the social and behavioral factors that too often sabotage optimal risk taking.
“Suboptimal strategy in sports causes no net harm, and gives quants something to feel smug about, even if the jocks are still more popular.”