Friday, December 23, 2016

On The NHL Scoring System (Part II)

Part I.

Goodhart's law is the bane, the safeguard and the watchdog of everyone who tries to make conclusions from sample data. The "Schroedinger Cat of Social Sciences" practically says, if you want people to do X, but you reward them for doing Y, they will be doing Y rather than X. We start seeing that in the "possession analytics", based on shots taken, that the players begin to shoot from everywhere to get their possession ratings up. But we digress - the topic is the scoring system, we'll save that note for another blog entry.

We want the NHL hockey to be spectacular. That's the main objective (beyond being fair and competitive, otherwise look for Harlem Globetrotters). In the past the spectacular was fighting as much scoring and winning games, but that taste of the public changed, and the fighting went away. It was not directly related to scoring and winning, it was just an extra free show provided.

Now we're left with scoring and winning. These two are closely tied, and not necessarily as a positive feedback, since not allowing your opponent to score also helps winning. A 2-1 win is practically just as valuable as a 7-2. So in the mid-2000s, the winning objective, the points objective took over the scoring objective. And from the previous post we see that the existing 2-2-1-0 points system encourages low-intensity game preferably slipping into the OT. On the other hand we also noted that the 3-2-1-0 points system would encourage teams to clamp down and protect their minuscule leads. Looks like a circle to break...

Well, here comes Goodhart's law. You want teams to score, or at least try to score, but you reward them for achieving points. So what they do is concentrate on getting points. Therefore, if the NHL want to see score-oriented hockey, the NHL needs to reward scoring, and not points. Still, the points have been used to determine playoff spots, so something has to give.

First, let's take a wild ride by suggesting that we rank teams by the amount of goals scored. That would lead to a pretty drastic change and the end of hockey as we know it. This will lead to situations where a team might play for a period without a goaltender in a playoff race. In general, the goaltending position will deteriorate, and aren't we loving the spectacular saves just as we love slick goals? Probably, that would be too much.

Thus, we can mitigate to allow the goal differential to be the ranking criteria. At the end of the season, the teams with the higher goal differentials will be ranked at the top, and the wins-ties-losses, well, they get relegated to tie-breaks. The incentive to score rather than to hold the opponent increases, because while now the competitors in their games cannot score more than two points, they still can score a bigger goal differential! All the lazy skating to finish the game after it's 4-0 or 5-1? Gone.

This idea is actually not novel. It's been used for a long while in team chess tournaments. Such tournaments consist of matches, where each player of one team plays against an opponent of the opposing team at the same time. Each player's individual score (win, draw or loss) is accumulated into the total score. So a match of 8-player teams, where one team had 5 wins, 1 draw and two losses ends up with 5.5-2.5 score, essentially "the goal differential". At the end of the tournament, the scores accumulate, and the teams are ranked according to them. You can see the crosstables of historical chess tournaments at the wonderful Olimpbase website.

And if you feel that the fact of winning or losing the game should be have more weight than just a tie-break (by the way, there will be less tie-breaks on goal differential), that is easy to factor in, just add a bonus "goal" to the winner, like it is done in the shootout now. Better, add two bonus "goals" for winning in regulation, one bonus "goal" for winning in the OT, abolish shootouts.

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