Breaking apart individual point percentage
Scott Reynolds over at NHLNumbers.com has written a series of articles on individual point percentage (IPP). Individual point percentage is defined as the number of points an individual has collected divided by the number of goals scored while the player was on the ice. In other words, it is the percentage of goals scored while the player was on the ice that the player either had a goal or an assist on. Scott’s articles are on individual point percentages for 2011-12, individual point percentages for the last 5 seasons and individual point percentages on the power play. Definitely go give them a read, as well as the comments, where some interesting discussions ensued.
At first I was skeptical of the value of IPP because essentially it only tells you how important the player is to the teams offense when the player is on the ice, and not really anything about the actual skill level of the player. A good player with really weak line mates can put up a pretty good IPP even if he isn’t a great offensive player. Or, a good third liner could have a similar IPP as a good first liner, but not be anywhere close to each other in terms of overall talent level. But, upon further thought I figured there would be some value in determining who is leading the offense and who might be deserving of a line promotion (i.e. might be too good for his current line mates) or a demotion (might be holding their line mates back). So, I decided I would look into IPP a bit further. I have calculated IPP for the past 5 years for 5v5 zone start adjusted ice time and only considered forwards with >2500 minutes of ice time over those 5 seasons. The top 30 players in terms of IPP are the following.
The above table is fairly similar to the top players that Scott identified so I won’t go into too much detail. Some guys that Scott identified, such as Jordan Eberle, didn’t make my list because he didn’t make my 2500 minute ice time restriction and because I am using faceoff adjusted ice time (eliminating 10 seconds after a zone face off) the numbers for others are slightly different. But more or less the lists are comparable.
The list above tells us who the guys that control the offense are, but there is a mix of goal scorers and play makers in the list. I wanted to split the list up further because for team building purposes I think it makes sense to want to have a mix of playmakers and goal scorers and not be too heavily weighted towards one over the other. I decided to calculate Individual Goals Percentage (IGP) and Individual Assist Percentage (IAP). Let’s start by looking at the top 30 players in terms of IGP.
There are certainly a few second and third line players sprinkled through the list but generally speaking those are some of the best pure goal scorers in the NHL and save for maybe Crosby they are more known for their goal scoring than their playmaking skills. Now, lets take a look at IAP.
There are a few odd names in there (Tootoo, Mayers) for example, but IAP is clearly doing a pretty good job at identifying the elite playmakers in the NHL.
One of my comments in Scott’s articles was that it might be interesting to reduce the importance, or even eliminate, the second assist as it may not be as important as the first assist. To see the impact of the second assists, let’s take a look at Individual Second Assist Percentage (ISAP).
Looking at the above list, I can’t say the second assist offers anything in terms of determining who the top play makers are. There really is a huge mix of players in that list, very few one would consider quality playmakers. It seems to me that the second assist is probably largely a useless point somewhat randomly distributed among players. So, that led me to looking at just first assists to identify which players are the best playmakers. The following table shows the top 30 players in terms of Individual First Assist Percentage (IFAP).
There were 7 players that were on the IAP list that are not on the IFAP list. Those are Mikko Koivu (85th in IFAP), Wojtek Wolski(81), Trent Hunter(56), Justin Williams(158), Radek Dvorak(113), Patrick Kane (32), Connolly(52), and Eriksson(122). The 7 players that replaced them are Vladimir Sobotka (34th in IAP), Ray Whitney(32), Brandon Sutter(219), Aaron Asham(93), Paul Gaustad(40), TJ Oshie(95), and Jason Spezza(69). Looking at these lists and the changes between IAP and IFAP it is difficult to say whether the IFAP list is better or worse, but my gut tells me that if you can’t tell the difference it is probably best to go with IFAP because everything I understand about hockey tells me that the second assist is almost certainly of lesser importance.
I have a few ideas of where to take this research from here, but as I stated above I have always had an interest in exploring team building from a statistical point of view and being able to statistically identify which players are more playmakers and which players more goal scorers is an important step in that direction. I want to get into exploring whether a line with two goal scorers (i.e. if the Rangers use both Nash and Gaborik on the same line) is counter productive and whether and how much players can improve goal scorers goal production. Too do that I’ll be looking at IPP, IGP and IFAP WOWY’s (with or without you comparisons).