In its ongoing quest to increase goal scoring, the NHL/NHLPA Competition Committee has proposed a rule change to modify defensive zone face-offs so that the defensive zone player must always put his stick down first. This replaces the current format in which the visiting team player puts his stick down first. (Neutral zone face-offs would continue to follow the existing rule.)
It’s worth noting that over the past five seasons, the offensive zone team has only won face-offs at even-strength 48.4% of the time. Maybe the league has noticed and wants to bump that number up to 50% or higher, and thinks that a rise in scoring would follow.
But would this rule change actually cause a significant increase in scoring? I decided to do the math and the result was only a miniscule increase in goals. Here is my methodology:
- I looked at every goal scored in the NHL from 2010-11 through 2014-15 and the outcome of the last face-off prior to that goal.
- I calculated the league-wide rate at which goals were scored (i.e. goals per face-off) by either team after face-off wins and losses in each of the following situations: (1) even-strength offensive zone, (2) power-play offensive zone/shorthanded defensive zone, (3) shorthanded offensive zone/power-play defensive zone.
- During these five seasons the home team won even-strength face-offs 51.6% of the time (or, a 1.6% advantage compared to a coin flip). While there are surely several factors contributing to this home-ice advantage, for the purpose of finding the maximum effect of the proposed rule change, I attributed the full 1.6% to the current rule forcing the visiting player to put his stick down first, and used this as an analog for the proposed rule.
- I set up a model of scoring per game based on the number of face-offs per game in each of the above situations and the observed rate of scoring after each face-off, according to whether the offensive zone team won the face-off. I adjusted the offensive zone face-off win percentage to be 1.6% higher in each situation as a result of implementing the proposed rule change, and calculated the resulting change in scoring.
- Here is all of this in a spreadsheet if you want to check my numbers or try plugging in some other number besides 1.6%. (Note that it won’t change the result much.)
So here is the change in scoring per game:
|FO/game||Change in goals per face-off after adjustment||Change in goals per game|
|Even-strength Off. zone||29.84||0.000113||0.00337|
|Power-play Off. zone||2.384||0.000307||0.000731|
|Shorthanded Off. zone||0.639||-0.000233||-0.000149|
Multiply that goals per game sum by the 1,230 games in a full season and we are talking about approximately 4.9 additional goals per year across the entire league. It’s an almost unnoticeable difference, but in a league desperate to increase goal scoring, it may be better than nothing.