What else does TOI% correlate with?

A few days ago I wrote a post looking at whether scoring chances and high danger scoring chances does a very good job at explaining variations in on-ice shooting percentages among NHL forwards. The short answer is that they do explain some of it (scoring chances better than high danger scoring chances) but is still a long way from being an ideal explanatory variable. We know that because I found that TOI% (the percentage of ice time the coach assigns to the player) had a far better correlation with shooting percentages.

In this post I want to take a look at how TOI% correlates with other metrics because it will tell us how coaches decide to dole out ice time. Using statistics from Puckalytics.com I come up with the following table of how well TOI% explains various metrics. To attempt to eliminate score effects I am using 8-year 5v5close data for all forwards with >2000 minutes of ice time.

TOI% vs R^2
GF60 0.568
Sh% 0.452
CSh% 0.441
CF60 0.340
GF% 0.310
CF% 0.157
CSv% 0.130
GA60 0.104
Sv% 0.089
CA60 0.003

It is clear coaches dole out ice time based on offense with a slight preference for shooting percentage over shot generation. Coaches don’t give the big minutes to the best defenders and especially not to those that focus on shot suppression.

It is interesting that coaches don’t seem to value defense as much as offense and especially shots against. It is probably an important reason why we find it so difficult to find trends and relationships in defensive statistics. It is a little odd because we know that some coaches clearly stress defense more than others and yet they don’t seem to be doling out ice time based on defensive results. This observation is likely the result of the belief that defense is a product of the system being employed by the team and less so the talent of the individual players where as offense is far more individual player talent driven.

If you can put the biscuit in the basket you will get a lot of ice time. For those who can’t, ice time is doled out more on who is most dedicated to playing the role they have been assigned in the system the coach has put in place.

What is interesting is if anything analytics is driving the bias towards offense even more. Guys like  Johnny Gaudreau (all 150lbs of him) and Tyler Johnson are all the rage right now. Watching my twitter feed I see analytically inclined Leaf fans getting excited for every small, skilled draft pick the Leafs make while ridiculing pick ups by other teams of big strong players like Los Angeles Kings with Milan Lucic.

Small, fast, skilled players that can move the puck up the ice and put the puck in the net and in while stay at home defensemen and defensive specialist forwards are getting pushed aside. I wonder how the table above will look 5 years from now.