How Game Management Has Broken NHL Refereeing
By: Jack Thomsen
Tags: Hockey, Sports, Game Managment, Competition, Analytics

On March 23rd, during the second period of Tuesday’s Nashville Predators vs. Detroit Red Wings game, long time National Hockey League referee Tim Peel was caught on a television hot mic, saying “…It wasn’t much but I wanted to get a f**kin’ penalty against Nashville early.” This comment from Peel came after he made a controversial call, giving a tripping penalty to Nashville player Viktor Arvidsson after he made minimal contact, which by all accounts should not have been a penalty. As Peel’s comment was on live television, backlash immediately broke out, with criticism from players, fans and coaches alike. There wasn’t just criticism, however, with many NHL figures coming to his defense, citing ‘game management’, and a necessity to call penalties to control the game. Peel had planned to retire after the season, and the NHL, as a result of his comment, suspended him for the rest of the season, giving Peel an early retirement. The NHL’s decision, however, doesn’t solve the issue, as Peel is part of a larger issue in refereeing. The concept of game management has become devoid of its well-intentioned origins, giving far too much power to NHL referees, who force an unfair parity which hurts the league’s future, and hockey as a whole.

In order to understand why game management is so detrimental to the NHL, we must establish why good, fair refereeing is essential to hockey, and uniquely important relative to other sports. In the NHL, penalties, and the power plays that result from them, are incredibly important. For those who don’t follow hockey, it is played with five skaters on each team, and a penalized skater is required to sit out for two minutes (of a 60 minute game), leaving the penalized team to play with four skaters for the duration of the penalty. It’s a tremendous advantage: on average, in the current NHL season, the average power play conversion rate was 20.40%, or essentially a one in five chance that a team scores. When the play is even with no penalties (5v5), that rate drops to 7.86%, showing an almost threefold increase in the likelihood of a team scoring a goal. Given that teams in the NHL average less than three goals per game, a 20% chance (and around 30% for the best teams) of scoring a goal is a massive factor in determining the outcome of a game. The role of penalties in hockey is substantial, and uniquely important relative to other sports: soccer has low-percentage free kicks, football has short upfield movements, and basketball has free throws worth two points out of a likely 100. Nothing compares to the gravity of an NHL power play. Penalties in hockey are extremely consequential, and so the refereeing issues plaguing the NHL are of the utmost importance. Given the deterministic nature of penalties, game management has a powerful role in hockey, especially when considering how the concept has long been abused in today’s NHL.

Game management isn’t an inherently negative concept, but the concept’s gross over-utilization has overrun its well-intentioned origins. Game management is supposed to be about keeping a game clean and safe, where good hockey can be played, instead of devolving to a full-ice brawl. To provide an example: In a game that is getting overly rough, with emotions rising, a referee may tell the players that the next player to start ‘something’ (causes tensions to rise) will get a penalty. This represents an effective usage of game management, as players tone down their behavior as to avoid the penalty, and the game continues without further incident. Unfortunately, game management often does not follow these same principles. Referees, in a broken attempt at game management, do not call penalties as they see them even in clean games, but instead to keep games even. Travis Yost of TSN succinctly described the issue: “Right now, the objective is not to call the game correctly, but to call the game equally. That’s a foundational failure.” For the most part, if one team gets a penalty, chances are that the opposing team gets the next one.

Michael Lopez’s paper Biased Impartiality Among National Hockey League Referees reported that “ingame analysis finds significant evidence that referees exhibit a form of ‘biased impartiality’ when a team has a negative penalty differential.” This means that penalties are called at a higher rate on teams who have had less penalties called on them, as refs try to even the game out. He also found that it is actually easier to predict the next penalty than the next goal, giving credence to the theory that officiating is based not on infractions, but on the state of the game and recent penalties called. A popular hockey analytics site, MoneyPuck.com, actually recently introduced a new live feature showing the probability that the next penalty is on the home team. The bar graph below, to the left, shows that as the share of penalties on the away (A) team increases (relative to the home team), the likelihood that the next penalty is on the home (H) team roughly increases, as referees attempt to even the game. As this trend is expanded to the larger season, we can see that teams that are the most penalized are the ones who also draw the most penalties. In the scatter plot below to the right, we can see a clear positive correlation between the amount of penalty minutes taken by a team and the amount of penalty minutes drawn by the same team.