Saturday, October 11, 2008

A Brief Intro To The Corsi Number

For those of you unfamiliar with the Corsi Number (or Rating) as a hockey metric, there's a good discussion of it here and here, but, simply put, it measures the number of shots directed at net while a player was on the ice at even strength, excluding empty net situations.

For example, if Player A skates a shift in which he takes a shot that misses the net, his teammate then puts one on goal and another teammate blocks a shot at the other end before the end of Player A's shift, Player A will have a +1 Corsi Rating for that shift. To put it in context, Henrik Zetterberg had the League's best Corsi Rating a season ago (the Caps top line was also quite good), and a bunch of Thrashers were at the bottom. Basically it's another tool in the analytical arsenal to guage a player's even strength effectiveness. Got it? Good.

We'll be looking at the Corsi Number throughout the year, but here are the Corsi Ratings from last night's game. A few things jump out:
  • The Mike Green-Shaone Morrisonn pairing's combined +17 is quite good (and it's worth noting that the two were the team's top two in even strength ice time).
  • The Jeff Schultz-Milan Jurcina pairing's combined -10 is pretty bad (and it's worth noting that Jurcina got the least ES ice time of any blueliner - had he gotten more ice... ).
  • The fourth line was a combined +14, the third (Michael Nylander) line was -3,the top line was +3, and the Alex Semin line was +12 - having the last line change paid off for Atlanta, as Ilya Kovalchuk matched up against the Nylander line and Schultz pairing more often than any others.
  • The Caps dominated the game at even strength, with a combined +53 rating.
Granted, you don't need an advanced degree in statistics to know that with better penalty killing and a key save or three (and/or a softy or two from Kari Lehtonen) the Caps could have won last night. But the Corsi Ratings shed a little more light on who did what and are worth keeping an eye on, especially in judging the effectiveness of line combos and D-pairings.

1 comment:

The Falconer said...

The Caps dominated the Thrashers 4th line at ES last night. Kovalchuk's line was only about +3 each which really isn't good enough when you are the home team and have the last change.

For Capitals Mike Green was very good last night, so it looks like he is continuing the breakout performance he had last year.