Zebra Psychology
A favorite line of referees—known to hockey fans as "zebras" because of the stripes on their uniform—is that they call the same game every time, regardless of situation. "A penalty is a penalty," in other words. Such immunity to context is admirable, and indeed the whole point of officials in the first place. But officials are also human, and humans err in fairly predictable ways. How does this show up in the game of hockey? Let's take a look:
Rule #1: A penalty is more likely to be called against a team on the power-play and less likely to be called against a team on the penalty kill. For example, Parise clearly trips McDavid in the following clip:
If Parise had done that at regular strength, the ref's arm would have shot up like he had an answer to a question. Instead, it went uncalled because the Oilers were on the PP.
Rule #2: A penalty is more likely to be called when a change of possession occurs. Another factor in the no-call above is that Edmonton was able to hold onto the puck. For close calls especially, referees let the outcome of the infraction make the decision for them. If no change of possession occurs, then the idea is: "no harm, no foul." Here's an even more egregious example:
Rule #3: A penalty is more likely to be called when a scoring opportunity is taken away. The following clip illustrates this in two ways. Have a look:
The fact that referees are especially twitchy around scoring opportunities explains why Marchand was not given a penalty for something that, had Sandin done to him, would likely have resulted in a trip to the "sin bin." I.e., Sandin was not a scoring threat when he got a twig to the jaw. Secondly, if Sandin had cross-checked Marchand after Marchand shot the puck, he would have had a better chance of getting away with it; but if he did it as or before Marchand shot, then there's no way he would have walked away free (from the ref or from Marchand).
Now, I don't have as much evidence for this next point, but it's possible that this rule operates on a much broader understanding of "scoring opportunity." For example, isn't McDavid in the slot more dangerous than Kyler Yamamoto or Codi Ceci? Wouldn't hooking McDavid, then, prevent a greater scoring opportunity? And therefore shouldn't a more minor hook against McDavid be called than against Yamamoto or Ceci? I'd be curious to know what fans think of this.
Rule #4: A penalty is more likely to be called on the team with the fewest penalties so far. Make no mistake that officials have a "counter" in their head and know when they have called more penalties on one team than on the other. A difference of 2 or less is considered part of normal variance, but after that, referees become a bit worried that their neutrality will be called into question.
Interestingly, this bias rewards clubs with great special teams, which is part of the reason the playoffs can be so unpredictable. Sure, one team might be better than the other at 5v5, but the weaker even-strength team can take advantage of referees' "reciprocity bias" by creating a gameflow with many infractions, knowing that they'll receive a "rebate" on whatever penalties they take in the form of balancing calls (terms and conditions apply). Keep in mind that balancing calls are different than make-up calls (next on the list).
Rule #5: Officials will try to correct their mistakes when and where they can. These corrections are referred to as "make-up calls." The most common way for a zebra to make a mistake is by missing a penalty or calling one that wasn't. But refs can unfairly influence the game in other ways, too, such as getting in the way of the puck. In any case, the only way to make things right is to skew the next call in favor of the team that was unfairly impacted.
What can we say about the last two rules in general? Basically, that there is a subtle give-and-take occuring deep in the minds of officials, an implicit sense of fairness honed over their many years presiding over the game, that influences their decisions. And we can see the common tactics of coaches—of feigning indignance over everything—as appealing to this deep-seated judge within. Coaches are constantly trying to nudge on that fairness system so that referees will think the coach's team is "owed" one.
Rule #6: Penalties are less likely to be called in critical stages of the game or season. Officials have been explicitly instructed to call the game consistently throughout. They are not supposed to "put their whistles away." On the other hand, nobody wants the referees to determine the outcome of the game—referees included—and I have a sense that even the zebra braintrust would allow for a little bit of "let 'em play." In any case, we can see this tension—between calling the game consistently and letting the players determine the outcome—working itself out in the below highlight:
Necas clearly gets hooked on the entry, but there are many factors contributing to the no-call—first and foremost, that it's quadruple overtime in the playoffs. But the Canes being on the PP (Rule #1) and the puck not changing possession (Rule #2) also undoubtedly factor in.
Here's another example. Watch #17 in black (Killorn):
Clearly, Killorn gets away with a trip. Just as clearly, he gets away with it because of the stage of the game. (If you listen closely enough, you can hear someone politely shouting for a penalty in the background.)
Rule #7: All else being equal, referees would prefer not to call a penalty. Meaning, if both sides commit a misdemeanor, better to call it a wash and avoid the paperwork. The video below is a solid (albeit subtle) example. Marner gets slightly interfered with as he's back-skating, and then slightly trips Coleman a few seconds later. The ref is happy to call neither:
Rule #8: Refs can be fooled by tell-tale signs of a penalty. Referees are instructed not to make a call if they don't see it, and while they often do an excellent job of this, they will occasionally deviate if the clue is reliable enough. In the game of hockey, there are certain micro-movements that, nine times out of ten, indicate that a penalty has taken place. Examples include: players falling over (tripping), twisting their body (hooking), or snapping their head back (high-sticking). Even if the referee hasn't seen the entire sequence, sometimes the aftermath can be enough of an assurance.
That being said, players displaying this behavior by no means are guaranteed to get a call. Nobody knows this better than Alexei Kovalev:
Despite displaying the tell-tale sign of being slashed (Rule #8) and turning the puck over (Rule #2), Kovalev didn't get the call, and looked like an absolute moron instead.
Rule #9: Officials love to reward hard work. At bottom, referees have a soft-spot for blue-collar types, which helps to explain the following:
Batherson gets the call not because he was hooked or tripped, but because he outworked Tuch. It was the equivalent of a lifetime achievement award, except in this instance, for a single shift.
As much as refs love to say they call the game the same way every time, regardless of the situation, the reality is that they don't. The above rules are merely the rough outlines of what could be made, one day, into a precise catalogue of exactly how referees deviate from the ideal they are striving for as impartial enforcers of the rules. I am NOT saying, by the way, that zebras do a bad job. On the whole, I think NHL refs are excellent. But they are also human, and humans err in predictable ways.
Stay innocent,
Josh
