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.