Re: RPI 2013/14 Part III: Maximum Overdrivel
Who was the more effective team on the power play? A or B?
You are confounding two distinctly different questions. "Effective" to me suggests a multi-variate metric, not a one-dimensional one. By one possible metric, the two power plays you described would result in an equivalent number.
Look more closely in the way you described your question: Team A actually had four power plays, each one of them thirty seconds long. They scored on one of them. Team B had one power play, two minutes long, and scored on it.
By this metric, Team B scored a goal on 100% of its power play chances while Team A scored a goal on 25% of its power play chances. This is a different metric.
It's not that one is right and the other is wrong, it is that they are complementary.
Let's call "goals scored per two minutes of man-advantage" the "efficiency" metric. Let's call "number of times scoring per power play" the "conversion rate" metric.
You tell me:
Team A had an efficiency rating of 1 goal / 2 minutes, and a conversion rate of 25%.
Team B had an efficiency rating of 1 goal / 2 minutes, and a conversion rate of 100%.
Which is more "effective"?
My answer would be that a one-game sample is too small a data set from which to generalize. I think it would be quite interesting to observe how these two different metrics played out over the course of a season.
As you so astutely pointed out, if there is a significant variance between the two metrics over time, it would clearly be an indicator that the team either (a) committed a lot of penalties during the power play, or (b) was able to draw quite a few additional penalties during the power play, leading to 5 on 3.