Last month I discussed Ian Levy’s findings on which coaches are most effective at doling out minutes, in which Alvin Gentry was ranked the sixth-most effective coach of the 45 analyzed.
Levy re-calibrated his approach ”to create a method that compares the talent level of a roster to the quantity of time that a coach was able to get that talent onto the floor” so that coaches like Phil Jackson and Doc Rivers don’t get as much of an advantage for making the obvious decision to play their All-Stars big minutes. He describes his new method like this:
“For each team, I looked at all the five-man units that played at least five minutes together and calculated what percentage of those units finished the season with a positive Net Rating. I then calculated what percentage of total minutes were played by those positive units. If a coach distributed minutes completely evenly, with no regard for a lineup’s effectiveness, those two percentages would be equal. Unsurprisingly, that was not the case in any of the seasons I looked at. So to restate, we’re comparing the percentage of lineups which outscored the opposition, with the percentage of time those lineups were on the floor. For our purposes here, we’ll consider the difference between those two percentages, positive or negative, as a representation of a coach’s ability to manipulate their roster.”
As things turned out, 52.6 percent of Gentry’s lineups outscored the opposition and he played them 69.9 percent of the time, giving him a 17.3 percent differential that ranked fourth in the NBA behind Jackson, Stan Van Gundy and Rivers and just ahead of Doug Collins, Rick Carlisle, Tom Thibodeau and Gregg Popovich. By this measure at least, Alvin Gentry is an elite coach.
Levy was a bit surprised to see Gentry rank so highly, and without looking at his data I would assumehas a lot to do with it. Nash’s +/- has been so high the past few years and he has played so many minutes that I would assume Gentry playing Nash-led units on its own would make him look pretty good.
Furthermore, a lot of this has to do with 2009-10 when he truly did possess a Midas Touch. That year 60.6 percent of the Suns’ lineups produced a positive result and he played those units 78.6 percent of the time (the seventh-best such mark of the past four years) for a 18.0 percent differential.
Last year just 46.7 percent of Phoenix’s lineups were in the positives but they were played 60.9 percent of the time for a 14.2 percent differential.
Under Mike D’Antoni in 2007-08, 59 percent of the Suns’ lineups produced positive results and they were played 75.8 percent of the time, lending even more credence to the Nash factor.
One drawback to this method would be the fact that a bad team’s top unit will often be outscored because it frequently goes up against the top units of better teams yet said team’s coach will be dinged. Therefore, this piece of analysis still favors the coaches of good teams whose top lineups play big chunks of minutes that likely result in a positive net rating. Also, since all positive and all negative lineups are grouped together, coaches do not get as much credit for heavily playing a superior lineup and get too much credit for playing one that’s slightly above average and vice versa for the negatives.
Still, this method does a solid job of illuminating which coaches are finding the right combinations, and in this regard Alvin Gentry has done a fabulous job for the Suns.