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# Quality of Competition

QOC is a metric that tries to quantify the quality of your opponent.

I'm getting tired of this guy's picture. When we post an article, we get a gallery of suggested photos. For almost two months, it's been Austin Poganski. One more reason I can hardly wait for training camp to start.

Quality of Competition obviously matters. If you play better opponents, you will have less success. QOC tries to quantify the quality of your opponent.

Teams

The QOC metric for teams is Corsi QOC. For teams, it's pretty easy to calculate. If the Blues have a Corsi of +5, their QOC as an opponent is +5.

So if the Blues play the Kings and the Kings have a Corsi of +10, the Blues are facing an opponent with a QOC = +10, and the Kings are facing an opponent with a QOC = +5.

Over the course of the season, Team QOC pretty much evens out. The range is about +0.7 to -0.7. The bad teams in the West tend to have the highest QOC and the best teams in the East tend to have the lowest QOC.

Either way, the net effect is pretty small. At 3600 minutes of 5v5 hockey, teams are involved in about 6000 Corsi Events. A QOC of 0.7 works out to about 40 Corsi Events either way.

Players

There are three basic approaches to QOC metrics that get used commonly: Corsi QOC, Corsi Rel QOC, and Time On Ice QOC.

Corsi QOC

Corsi QOC is based on (wait for it!) Corsi. If you play against a player with a Corsi of +10, your QOC is based on that +10. For example, if you play one shift against players with Corsi of +6, +8, +10, +12, and +14, your QOC for that shift is (6+8+10+12+14)/5 = +10. Do that for every shift and voila! QOC.

The range of QOC you see depends on the number of games played. More games tends to result in a narrower range. These are typical values over the last few years.

 Games Played Maximum Minimum 40 plus 2.5 -2.5 70 plus 2 -2

Once again, over a full season, the effect is small. 40 games is about 600 minutes of 5v5 hockey, which is about 1000 Corsi events. QOC = 2.5 works out to about 25 events over those games. 80 games is about 1200 minutes and about 2000 events. QOC = 2.0 is about 40 events.

Corsi Rel QOC

Corsi Rel QOC is computed the same way as Corsi QOC, but the opponent's Corsi Rel is used instead of their Corsi On.

The difference between using Corsi for QOC and Corsi Rel for QOC is, I think, qualitative. Players with high Corsi Rel values tend to be the best players on their team, even if their team sucks. For example

 Player Corsi Corsi Rel Ryan Reaves -7.06 -17.4 Jordan Eberle -7.49 6.7

Players with a high Corsi Rel QOC were being sent out by their coach against the other team's top players.

Corsi Rel QOC usually has a little bigger range than Corsi QOC. Corsi Rel QOC sometimes ranges up to +/- 3.5. Last season, however, the range was about the same as Corsi QOC.

Time On Ice QOC

TOI QOC was an interesting innovation at Extra Skater. TOI QOC was calculated the same way a Corsi QOC, but used the opponent's average 5v5 TOI instead of Corsi On. Personally, I think TOI is basically a proxy for Corsi Rel. Coaches play their best guys as much as they can. Since Extra Skater is gone, unless someone else starts publishing TOI QOC, it will probably fade away.