Via TrueHoop, our friend Kevin Pelton writes on a new technique with which to measure coaches. A researcher named Jeremias Englemann used the adjusted plus-minus technique applied to coaches, treating them as a sixth man. Plus-minus measures a team's success (points scored minus points allowed) when a player is on the floor. On-off ratings compare the plus-minus when a player is on the court with the plus-minus for the team when the player is on the court. Adjusted plus-minus adjusts for the quality of teammates and opponents.
Coaches, then, would be assessed in how much better or worse players perform under them versus other coaches, adjusting for teammates and opponent quality. According to Englemann's data, using a data set covering the last five seasons, Paul Westphal has an adjusted plus-minus of +1.4. That ranks a solid No. 14 among the 70 coaches in the data set.
Most of the impact -- +1 point per 100 possessions -- is on the offensive end. The other +0.4 points per 100 possessions is found on the defensive end. This is a reassuring thing; even if you place little faith in the measure, at least it doesn't say he's godawful, right?
But there's something in KP's piece that I find more interesting than the numbers.
In a more general sense, Engelmann's results confirm the conventional wisdom that coaches make a greater difference at the defensive end of the floor. Coaches' ratings, both positive and negative, are much larger on defense than they are on offense. That suggests that it is wise to favor defensive-minded coaches over their offense-first peers. A team's success on offense depends largely on personnel, as [Mike] Brown's track record in Cleveland shows. Talent matters on defense, too, but Brown has shown the ability to consistently mold defenses better than average, no matter what kind of lineups he's given.
You may remember that I wrote about this subject back before the Westphal hire. (I was stumping for Mike Budenholzer and Tom Thibodeau.)
[Dean] Oliver found that four coaches took different franchises to the top 25 defenses list: [Phil] Jackson, Pat Riley, Larry Brown and Lenny Wilkens. That's a substantial figure -- those coaches take up nine of the 25 best defenses. Other coaches (Gregg Popovich, Frank Layden) on the list only coached one franchise. Almost the entire list is made up of coaches known as master motivators (Jackson, Wilkens), complete hard-asses (Riley, Popovich) or both (Brown). There are really very few surprises on the list ... as opposed to the offenses list, which boasts Del Harris (who had Kobe and Shaq for a few years ... and a sub-.500 coaching career outside of L.A.) and Dick Motta (whose coaching crimes you know well -- his great season with Blackman, Harper and Aguirre landed him the Kings contract).
Judging by Oliver's findings -- and this is me speaking, not Oliver -- it would seem a great offense absolutely depends on great offensive talent, while coaches can significantly impact a team's defense. Even Dick Motta! can coach a great offense -- it takes a great coach to pull off a great defense.
So this is the other side of the coin: Westphal is considered a good coach under this analysis ... but he doesn't help much where it matters most: defense.
Fascinating subject with incredible ramifications.