Why luck plays such a giant role in ice hockey

The NHL playoffs are almost like a second season – two months of tough, relentless games where the highest teams vie for a probability to win Lord Stanley's Cup.

The 16 hockey teams that made it to the postseason owe much of their success to the talents of their players and the tactics of their coaching staff.

They also needs to thank their lucky stars.

In my recent book “The random factor“I explain why of the five major U.S. team sports—basketball, football, baseball, hockey, and soccer—ice hockey is the one with probably the most luck in wins and losses.

Skill vs. probability

Using a mathematical approach called “true rating theory“Analysts were in a position to assess the contribution of luck to a team’s overall success.

This statistical technique uses the variance by way of skill, probability, and end result to estimate the relative importance of skill versus probability in determining outcomes.

In the NHL it’s estimated that the Contribution of luck to a team's seasonal balance is around 53%. At the opposite end of the spectrum, only 12% of an NBA team's success is resulting from luck.

The other three sports are grouped in the center, with a couple of third of their position in the general standings depending on luck.

More scoring chances are high necessary

How could these differences be understood?

An important factor is the variety of scoring probabilities a team has. The more probabilities a team has, the less luck plays a job within the end result.

In a typical NBA game, each team may rating 35 or more baskets during a game, whereas in an NHL game, a team may only rating a few times. Luck plays a much greater role when the probabilities of scoring are fewer. In such situations, a lucky hit is more likely to choose the end result of a game.

One can see that with coin tosses. If you flip a coin ten times, you might well find yourself with heads or tails seven or eight times, despite the fact that the general probability of every flip is 50%. With so few throws, there may be significant deviations from what should theoretically occur: five heads and five tails.

However, for those who flip a coin 100 times, you'll probably find that just about half of those coin flips come out heads. The more events – on this case, coin tosses – that occur, the more likely the ultimate tally is to reflect the underlying probability.

In sports, too, the players' skills come into their very own when there are more scoring opportunities. In the NBA, a player can try greater than 20 shots in the middle of a game – possibly half of that – so that they have more probabilities to point out off their skills and influence the end result of a game.

Distract, distract, distract

The oversized role of luck in ice hockey can be explained by one other factor.

Although the rating in typical NHL games is kind of low, each team can easily attempt 45 or 50 shots. This would seemingly refute the reason that the variety of events or opportunities influences the role of luck within the end result of a game.

But anyone who has ever watched an expert ice hockey game can understand the serendipity that takes place on the ice. Skates or sticks often deflect shots randomly when players cross the trail of a puck. Pucks can experience strange bounces as they travel across the court. Goalkeepers could simply be in the appropriate place at the appropriate time.

Hockey players watch as a puck flies over a goalie's shoulder after being deflected.
Nashville Predators center Colin Wilson (33) watches a deflected shot fly past Chicago Blackhawks goaltender Scott Darling during a playoff game in 2015.
AP Photo/Charles Rex Arbogast

In short, there is important randomness between the time the hockey stick hits the puck and the time it ultimately lands.

Plus, it's just difficult to attain a goal in ice hockey. The net is small and the goalkeepers are tall and wear bulky pads. Pucks have little or no space to splash through.

In all sports, probability and luck ensure excitement and fascination in these competitions. You can never be completely sure how the ball or puck will bounce. Even in case your team is heavily favored, the random factor at all times plays a job.

Nowhere is that this more evident than in ice hockey.

Despite all of the predictions from experts and oddsmakers, fans of NHL playoff teams can be smart to do something else: keep their fingers crossed.

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