Brendan Morrison and the failure of Corsi
Last night after news came out that Brendan Morrison had re-signed with the Calgary Flames, Kent Wilson tweeted the following:
Morrison back in Calgary. Check out his corsi tied rating fellow stats nerds: http://bit.ly/q1ywUj
The link is to the Calgary Flames 5v5 game tied corsi ratings which show Morrison had a 0.452 corsi rating (Corsi For %) which was dead last on the Flames. The problem with jumping to the conclusion that Morrison is bad is two fold:
1. Corsi generally speaking isn’t good at evaluating players.
2. One year of 5v5 game tied data is not enough to evaluate players, even with corsi.
Lets take a look at Brendan Morrison over the past 4 years and I’ll show you exactly what I mean. First lets look just at 5v5 any game score situations.
In each and every year the goals for percentage is significantly higher than his corsi for percentage. His corsi ratings make Morrison look mediocre at best but his goal ratings make him appear to be quite good. This isn’t a fluke. It is occurring systematically, every single season, over 4 seasons in which Morrison played for 5 different teams (Vancouver, Anaheim, Dallas, Washington, Calgary).
Now what about 5v5 game tied situations. Morrison’s 4 year game tied corsi for percentage is 0.482, his 4 year game tied goal for percentage is 0.592 (which ranks 28th of 217 among forwards with at least 1000 5v5 game tied minutes over the past 4 seasons).
Personally, I’d rather have good goal ratings than good corsi ratings. Morrison is a good signing by the Flames.