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, and for the most part that is what I saw. The exception being centers being given more influence and wingers less, this is because players that are listed as being centers often play the wing where as wingers are less often on the ice playing as centers.
The proper method for identifying the contribution a position has on offense and defense is not to sum up their contribution but to look at the variation observed in the players ratings for that position. Recall that with my ratings a 1.00 is a neutral rating or an indication that the player has no positive or negative effect for that aspect of the game (offense or defense) compared to the expected level of performance when quality of competition and quality of teammates are considered. Anything less than 1.0 implies a negative impact and anything above 1.0 implies a positive impact. So, if a position can significantly influence offensive production then we should see a larger variance among centers HARO+ ratings. The good players at that position will have ratings well above 1.00 and the weaker players well below 1.00. For positions that do not have a significant impact we should see players at that position have ratings much closer to 1.00 and less variation between the best and worst players. So, here is what we find.
The above uses four year ratings (2007-11) and only forwards and defensemen with at least 2000 minutes of 5v5 even strength ice time and goalies with 3000 minutes were considered. The resulting group included 122 centers, 85 LW, 103 RW, 194 defensemen and 53 goalies.
On offense, the three forward positions have significantly higher standard deviations (0.162-0.171) than defensemen (0.095) which intuitively makes sense. It means that forwards have a greater ability to influence offensive production than defensemen which is no surprise. Defensively the greatest variation in HARD+ occurs for centers with defensemen and wingers more or less the same a step below centers and goalies another step back again. It is possible centers rank ahead of wingers and defensemen in part because they are the ones who take face offs and thus are a major factor in the team gaining control of the puck.
The other thing that you’ll notice is that for HARO+ the average rating is well below 1.00 for both the forwards and the defense. This probably indicates that the big minute players are the offensive players which makes the average rating (which is ice-time neutral) well below the ice time weighted average (which in theory should be very close to 1.00). Lets take a look at how the players rate according to total ice time.
For the three forward positions it is clear that the top offensive players get the most playing time while players who get less playing time are slightly better defensive players. This isn’t really a big surprise as the majority of a team’s offense comes from their top line(s). The question is, how much does coaching/playing style influence the results. By that I mean, would first line forwards be better defensively if they were on the third line and asked to play a defensive role as opposed to being on the first line and being asked to and expected to produce offense? I suspect for most players the answer would be yes. I suspect the reverse (third/fourth line guys having better offensive ratings if given first line roles) is also true, but probably to a lesser extent.
For defensemen the best offensive defensemen still get the most ice time, though the variation is much less than seen with the forwards. Defensive ability seems to have very little variation across ice times until you get to the lower minute players who appear to be more defensive specialists.
As one would expect, the best goalies are given the most time in goal. There were 9 goalies with greater than 10,000 minutes of 5v5 ice time and all had ratings over 1.00 except Tomas Vokoun whose rating was 0.978. According to my rating system, Vokoun is a pretty ordinary goalie which means he is likely one of the more over rated goalies in the NHL because some (or most) consider him elite. It’ll be interesting to see where he ends up this summer as a UFA and how that team performs next year. Could Vokoun be another goalie failure in Philadelphia? Could happen.