Hey there! It’s been a bit, but I promise I’ve got something special for you.
With some elbow grease and help from Game Over Network contributor Jordan Hachey, we have tracked minor penalties and power plays for the entirety of the NHL up to the Olympic break, meaning we have a database with over 10,000 datapoints to work with and learn some stuff.
For this column, we’re going to be looking at league-wide trends, then looking at how much variance there is across the league. We’re not going to dig into the Canadiens specifically yet, because there’s a lot to go over, and no one wants to read a 20,000 word article with 500 graphics, right? Right.
Establishing Standards
We all know that game management exists, that how the game is officiated changes based on the score and the time remaining in the game. Now that we have tracked all these infractions and put them together in a database, we can see exactly how differently the game is officiated based on these factors.
At a hair over six calls per 60 minutes of play, referees exert the smallest amount of direct influence on the game while the score is tied. As soon as a goal is scored, penalty calls increase substantially (+19.8% overall) as the dynamic of the game changes.
At a league-wide level, trailing teams receive a 27.6% boost to their power-play opportunities, while calls against don’t see a statistically significant change, with the rate of coincidental minors increasing by 69%.
What this means is that while a team is leading, they can be expected to to receive just 44.2% of the power plays, whereas when a team is trailing, they can expect to receive about 55.8% of the power plays.
The score is only part of game management though. How far into the game were are also factored in.
Broken down by period, we can see that the second period is filled with far more penalty calls than the other two. I looked at a few different reasons for why that might be, but the only thing that makes sense is that it’s the long-change period for both teams. Because it’s harder to get to the bench, players are a bit more exhausted near the end of shifts, and more likely to take penalties. That provides a natural reason for penalty calls to drop in the third period, giving a perception of game management that is more due to the game itself than any external pressure.
However, while a higher percentage of calls in the second period are coincidental minors, that increased share of total penalties that don’t result in a power play doesn’t diminish in the third period, it actually increases.
That means that while the total number of called infractions per minute played doesn’t substantially change between the first and third periods, the ability to gain an advantage drops pretty significantly. After the first period, the rate of coincidental minor calls goes up by a whopping 86.2% in the final 40 minutes, and that really hits hard in the third period where there are 22.2% fewer power plays to be had than in the first 40 minutes of the game.
Breaking it down by period, I think it would be fair to see the way third periods are officiated as the NHL’s referees trying not to “influence the game.” Of course, we know that letting calls go also influences the game.
By period, it seems relatively clear that there is some game management going on in how infractions are called, but when it comes to the score, how much of that change is due to score effects on the game, rather than the refs themselves? While the score is tied, everything will be at 50% at a league-wide level, so let’s look at leading and trailing situations and contrast penalty differentials with shot-based metrics that we know are subject to score effects.
On the surface, share of power plays appears to track essentially perfectly with share of shot attempts (Corsi), producing nearly exactly the same results in both leading and trailing situations. That means penalty differential in different situations isn’t actually on officials, but is directly tied to the flow of the game, right?
On a league level, that appears to be the case, but I also have each team’s individual rates in all these metrics, and using that, we can calculate the R² values for a plethora of metrics to see if they actually have any predictive power for infractions that result in power plays.
The short answer is: nope. Using both all situations and five-on-five metrics for penalty differentials in each situation, the best R² value (or metric that explains the most variance in our dependent variable in power-play shares) is just 0.39 for shot shares in all-strength situations while leading, influencing the share of power plays a team receives.
In fact, leading situations at all strengths is the only game state where the flow of play seems to have an influence on power plays, with Corsi, goals, and expected goals all at 0.24 to 0.26 in R² value. However, all situations factor in power plays as well, so when you earn more power plays, you’re going to have a better control of shot-based metrics, so it’s difficult to distinguish how much that is influencing results.
At five-on-five only, the strongest R² value of all shot-based metrics remains in leading situations at 0.24, which, once again, is shots. A weak correlation, but it’s not bad advice to tell teams in leading situations to throw pucks on net as much as possible; you might earn a power play you didn’t expect.
While trailing, R² values for shot-based metrics range from 0 to 0.06, which means they essentially don’t matter at all in determining which team gets more power-play opportunities.
Out of curiosity, I also checked against overall penalty differentials using time on ice-weighted team heights, weights, and age, to see if any of those factors drastically influenced how penalties were called. Weight had the strongest R² value at just 0.11, so I’m going to say it’s not a big deal.
At a league-level, it appears that the application of the rules follows the flow of play and is more or less ‘fair,’ and without granular data this would be a great use of that old NHL idiom that ‘it all evens out over time,’ but we do have the granular data now.
And what we find for individual teams is that controlling play has almost zero impact on your power-play results.
Infraction types
What kinds of penalties are called most frequently in the NHL, when, where, and in what manner? That’s something we can now figure out!
The most common penalty in the NHL is the same as what we saw way back in December: tripping. Tripping is the toughest penalty to ignore. It’s hard to argue with a stick between the skates, but it’s also the infraction that’s most likely when a player loses body position close to the puck-carrier. Desperate reaches for the puck through bodies can get you in trouble.
What’s interesting is how different the kinds of infractions are depending on what division you play in.
For the most part, the differences between divisions in how the game is officiated is negligible, but the Atlantic division stands apart. Not only is it the most tightly contested division in the NHL by far, it’s nearly twice as ‘rough’ as the rest of the league, apparently.
A good portion of this is thanks to the two Florida-based teams, with the Tampa Bay Lightning and Florida Panthers accounting for a staggering 37.4% of the roughing calls in the Atlantic Division. Both teams throw a lot of temper tantrums, and both teams use post-whistle shenanigans to turn momentum during games. No team in the Atlantic Division sees fewer than 14.5% of their called infractions being roughing, while the other three divisions don’t even hit 11%.
We already know that coincidental minors go way up as a percentage of all calls in the third period, so it shouldn’t be a surprise that the third period sees a rise in roughing calls (+26.3% league-wide) and unsportsmanlike conduct calls (+18.3%). Those are infractions where officials have a lot of discretion that can be used to nullify power plays.
Now, what kinds of calls do the whistles get put away for in third periods?
The biggest drop isn’t actually shown on this chart, with the rate of too many men calls dropping by a staggering 61% in the third period. I didn’t include it because the long change in the second period is a bit of an issue there. There are more too many men calls in the second period in the NHL than the first and third period combined, but there are still fewer than half as many in the third period as in the first period. I’m not sure what to conclude from that other than officials decide it’s not something they want to call when the game is in its final stages.
The rest of the calls listed are about what you would expect, but the four largest drops all relating to obstruction gives a hint about what the NHL believes the game should look like when games are being wrapped up.
In third periods, teams are allowed to obstruct significantly more than the first two periods, and the odds are pretty good that if you do get called, you can convince the officials to give out a coincidental minor if you mix it up after the whistle. I would argue that this kind of baseline for third periods directly disadvantages teams built for speed and offence, while giving a big advantage to slower, more physical teams that need to obstruct to defend and attack.
From league to teams
From here, we’re going to drill down into how the NHL’s rule application weirdness has impacted specific teams, where outliers are occurring, and we’ll try our level best to discern logical reasons for those outliers where they can be found. As always, the database is available to everyone who wants to take a look free of charge; however, if you create content with it, please accurately source it and even link back.
Digging into teams individually would make this column incredibly long, so I’ll leave you with a tease for what’s to come. Thanks to my partner being a real scientist, with all this data available I was able to lean on her expertise to display things in meaningful ways despite dealing with mountains of datapoints.
Below, you will see all 32 NHL teams (unlabeled) displayed by their shares of power plays (coincidentals not included) in tied, trailing, and leading situations, as well as by period, with standard deviations of +2, +1, -1, and +2 graphed out to show how significant the outliers are in each situation.
For fans of the Montreal Canadiens, I will leave you with this: the Habs are essentially dead average while tied, and through the first 40 minutes of games this season. Yet they are the lowest dot in the trailing section, one of only three teams in the NHL that receive fewer than 50% of the power plays when they’re behind in games with the Washington Capitals and Anaheim Ducks.
The largest outlier in any fashion across the entire league is the Canadiens’ penalty differential in third periods. The lone dot all by itself on the far right and bottom of the chart. They are 2.67 standard deviations below the league average.
That is odd.
Andrew Berkshire is the former managing editor of Eyes on the Prize, and the founder of Game Over Network Inc. A Canadian, employee-owned sports media startup focused on platforming young creators across the country. Find Andrew live on YouTube after Habs games with Game Over Montreal, where you can also find Marc Dumont, Kay Imam, and Conor Tomalty to bring you interactive postgame analysis. You can join the Game Over Network’s Discord, and support us on Patreon as we employ over 30 young sports journalists and analysts across Canada’s seven NHL markets.
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