Wednesday, 7 May 2014

Lucky vs. Good Matrix

In any NHL season, there is considerable amount of luck involved that is played out on the ice and therefore becomes translated to the standings. The concept of luck in sports is a tricky one for most casual fans to fully grasp. Most people accept that luck plays a real role in the outcomes of games but what forms that luck comes in and how prevalent it is can be widely debated. Hockey is a game involving so many dynamic elements all occurring simultaneously, when it is put so eloquently by Brendan Shanahan it isn't too hard imagine why some aspects can be out of an individual's direct control:
But we need to put all this together while moving at high speeds on a cold and slippery surface while 5 other guys use clubs to try and kill us, oh yeah did I mention that this whole time we're standing on blades 1/8 of an inch thick? Is ice hockey hard? 
Sometimes the bounces will cancel each other out in the long run, sometimes they don't. Yes, playing an 82 game season helps even out the ups and downs, but not always. Too many fans still get suckered into starring at the standings and thinking that a teams point totals are a good indicator of how strong that team is. With this matrix I have created you, hopefully you can gain an idea of what teams were for real this past season and which were mere illusions.

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If you aren't interested in the methodology just skip to the next set of asterisks.

The skill portion of this matrix is fairly straight forward. I chose 5on5 Close FF% as a proxy for possession for fairly obvious reasons, mainly due to how closely it trends towards actually possession numbers. For those of you who may not be aware, controlling possession has been shown to be not only a very repeatable and consistent skill but also a very good predictor of future success.

The luck aspect of this matrix is much more open for variation and discussion. Using Rob Vollman's Team Luck calculator I was able to come up with a value based on five different luck attributes. Each of these attributes was able to be rated on a range of 1-5 (1 meaning irrelevant and 5 being extremely important). The actual luck score that each team received is an arbitrary number essentially but is good for being able to compare teams on the same scale. Here are each of the attributes and how I weighted each of them:

PDO 4/5 - PDO is the sum of a team's SV% and SH%. We know that PDO tends to trend towards 100 therefore we can conclude that any team with a PDO>100 is more likely to be riding an unsustainable hot streak and a team with PDO<100 should start to see the puck bouncing their way soon enough. This is probably the most widely accepted form of luck in the current NHL and was weighted highly accordingly.

Special Teams Index (STI) 2/5 - STI, like PDO is a combination stat in which you sum a teams PP% and their PK%. The same methodology of regressing towards a score of a 100 applies as with PDO. I rated this slightly less because while I believe there are some hot and cold streaks with regards to special teams, some teams via either coaching systems or player availability can maintain some outlier percentages.

Cap Hit of Injured Player (CHIP) 3/5 - CHIP is a metric provided by Springing Malik, which essentially helps us quantify the amount a team has been hurt by injuries during the season. It accounts for the how many games were missed by a player based and uses that player's Cap Hit to determine the value of that player to their team. It isn't a perfect metric for quantifying how detrimental each injury is to a team but it's still pretty good, therefore it gets a middle of the road ranking.

Post-Regulation Record 4/5 - The shootout and 5 minutes of OT have been shown to essentially be nothing more than a flip of a coin. While there is some skill in play via differentiating certain players and goalies the eventual outcome of these situations involves a ton of luck.

Record in One-goal Games 3/5 - It has been shown that winning games by only one goal isn't a very good indicator of a teams ability and that teams who have been lucky enough to come out on top in these tight games did so mainly due to the bounces going their way.


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Legend

Quadrants Playoffs
Good and Lucky 9/10
Good and Unlucky 3/7
Bad and Lucky 4/5
Bad and Unlucky 0/8

X-Axis: 5on5 Close FF% (Fenwick for percentage) - Farther to the right = Better team
Y-Axis: Calculated Luck Score - Closer to the top = Lucky



Some thoughts on the results:

  • Good and Lucky - The only team from this section not to make the playoffs was the Yotes who in reality were just barely a positive possession team with very low levels of luck anyways so it isn't crazy to see them not in the playoff picture.
  • Good and Unlucky - The Devils are probably the most interesting team in this subsection. Despite sterling possession numbers they were unable to overcome some of the worst bounces in the league this season. Another observation, the Red Wings snuck into the playoffs while the Canucks couldn't despite their equal unluckiness and Canucks better position might be more due to finding themselves in a much more difficult conference.
  • Bad and Lucky - I was definitely surprised to see 80% of the teams in this category sneaking into the playoffs. Colorado had an absurdly lucky season which makes up for their defects. The Wild, Canadiens and Flyers were not too bad possession so they aren't too much of a stretch. The Leafs were just awful despite having the 5th best luck overall.
  • Bad and Unlucky - Bad teams with no bounces going their way, tough to have much success with a formula like that. 

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