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

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How I Evaluate Players (and Why)

Over the past couple of weeks I have had several comment discussions regarding some of my recent posts on player evaluation and Norris and Hart trophy candidates which centered around which is a better method for evaluating players:  corsi vs goal based evaluation.  A lot of people, maybe the majority of those within the advanced hockey stat community, seem to prefer corsi based analysis while I prefer goal based analysis and I hope to explain why with this post.  I have explained much of this previously but hopefully this post will put it all into one simple easy to understand

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Persistence and Predictability

There seems to be some confusion, or lack of clarity, about my post on corsi vs shooting percentage vs shooting rate the other day so let me clear it up in as straight forward a way as I can. “Hawerchuk” over at BehindTheNetHockey.com writes the following: “I’m not totally sure what he’s getting at. People use Fenwick because it’s persistent, and PDO because it’s not. Over the course of a single season, observed shooting and save percentage drive results, but they are not persistent.” Dirk Hoag over at OnTheForecheck.com writes: “Here’s an example of when NOT to use correlation as

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Goal Rates better than Corsi/Fenwick in Player Evaluation

The general consensus among advanced hockey statistic analyzers and is that corsi/fenwick stats are the best statistic for measuring player and team talent levels.  For those of you who are not aware of corsi and fenwick let me give you a quick definition.  Corsi numbers are the number of shots directed at the goal and include shots, missed shots and blocked shots.  Fenwick numbers are the same except it does not included blocked shots (just shots and missed shots).  I generally look at fenwick and will do that here but fenwick and corsi are very highly correlated to the results

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Players Worth by Position – Revised

I wrote an article a few weeks ago about the offensive and defensive contribution (i.e. their HARO+ or HARD+ rating multiplied by ice time) of each position (C, LW, RW, D and G) but I have come to realize that my methodology is incorrect and thus the conclusions are incorrect (at least when looking at league-wide results).  The reason is, in my rating system contribution is evenly distributed among the 5 players on the ice so if I sum up all contributions of all players playing at a particular position I should see each position be given an equal share,

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Was Corey Perry more valuable in 2010-11 than Previous Seasons?

By all accounts, Corey Perry had an exceptional season in 2010-11 and this is particularly true down the stretch when he flew by Steven Stamkos for the lead in goals scored and pushed himself into serious contention from the Hart Trophy as the leagues most valuable player.  There is no doubt that Perry’s production level surpassed anything he had previously done in his career, but was he truly more valuable to the Ducks than in previous seasons?  Let’s look at the numbers. Season GP Goals Assists Points +/- PPG PPA PP Points 2010-11 82 50 48 98 9 14 17

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Players Worth by Position

Before I get into the main subject of this post let me first point out that I have updated stats.hockeyanalysis.com to include all 1, 2, 3 and 4 year player ratings that can be calculated using the last 4 years of NHL data.  For more information on my player ratings read this. I generate offense, defense and overall ratings for each and every player in the NHL and I wanted to get an idea of how much each position contributes to the performance of the team.  To accomplish this I multiplied each players offensive and defensive ratings (HARO+, HARD+) by

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Driving/Suppressing Shooting Percentage

The guys over at Behind the Net have initiated a ‘prove shot quality exists’ competition and in response to that Rob Vollman took a quick and dirty look at shooting percentage suppression.  As I showed the other day, Rob’s logic was a little off. Rob started off by identifying a number of players with high on ice save percentages over the past 3 seasons.  Some of these guys included low minute players mostly playing on the fourth line against other fourth line caliber players, but there were a handful of players who played relative significant number of minutes and still

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Score Effects on Shooting Percentage

I thought this debate had been fully hashed out already but apparently some people still don’t believe that the game score has an impact on shooting percentage (and shot quality).  The following table shows the shooting percentages by game score over the past 3 seasons (2007-08 to 2009-10) during even strength situations where neither goalie is pulled for any reason (including delayed penalty situations). Situation Shots Goals SH% Prob<= Prob> Down2+ 23650 1852 7.83 0.3794 0.6206 Down1 30447 2356 7.74 0.1696 0.8304 Tied 60753 4427 7.29 0.0000 1.0000 Up1 26842 2288 8.52 0.9999 0.0001 Up2+ 19351 1779 9.19 1.0000 0.0000

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Kings may regret Jack Johnson Contract

The Los Angeles Kings have signed Jack Johnson to a 7 year contract extension which will pay him $3.5 million the first 3 seasons and $5 million the final four seasons with a cap hit that works out to a cap hit of $4.36M per season.  So the question is, is it a good deal for the Kings?  I am not sure it is. First, let me start off by saying that I really don’t watch the Kings that much so I haven’t seen Jack Johnson play all that much.  My comments here are based purely on a statistical analysis.

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