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Wednesday, March 17, 2010
Why I can’t stand the “one run games” as a category
This has bothered me to no end. I’ll try to explain why in my way, which won’t be any good. And then I’ll link to a great explanation. For one thing, the home team can get 0 to 3 less outs per game to score than the visiting team. Secondly, what is a close game all game can get undone by a never-ending ninth inning. So, while the teams may have been strategizing as small-ball for 8 innings, makes it look like a blowout. The “one-run game” is an AFTER-THE-FACT categorization of the game, but we use the category to describe it in real-time or before-the-fact scenarios. A much better way to categorize a game as close is to use win expectancy and leverage index. The closer the win expectancy is to .500 for one team, and the higher the LI, then the closer the game. There. That’s what we want.
Here’s Hawerchuk on the NHL:
In the last 90 seconds of a one- or two-goal hockey game, the trailing team gets much more value out of scoring a goal than they do out of preventing one. Hence the strategy of pulling the goalie. The net result is that lots of one-goal games become two-goal games, and lots of two-goal games become three-goal games.
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We can remove the effects of pulling the goalie by looking at the score before the last two minutes of the third period:
Prior to 18:00 No ENG ENG
1-goal 33.3 32.5 24.3
2-goals 21.7 20.6 22.5
3-goals 12.2 11.9 17.9ENG = empty net goals
It turns out to be a very minor difference. But fundamentally, there are a lot more one-goal games and a lot fewer three-goal games than we’d think based on the score at the end of regulation.
But the presumption is that how players or teams perform in one-run games is a measure of how they perform under pressure, and/or a measure of how lucky or tenacious they are. This means the player or team knows it’s a low-scoring, tied or one-run game and is reacting accordingly. A player or team can see the scoreboard and see it’s a one-run game. They’re not exactly going to be able to calculate WE in their heads in the bottom of the 7th… so don’t throw out calling them one-run games.
WE and LI are totally valid and correct for evaluating close games during the season in a larger context though.