We blogged earlier about the best coaches in the NBA. The numbers show that the best coaches generally make their impact felt on defense, not offense. A possible explanation is that players have less incentives to play defense, since they are paid mostly based on their offensive statistics. Thus, a great coach is one who can get his players to commit play hard on the defensive end.
I wonder, however, if good coaches impact all players equally. Can a good defensive coach (e.g. Thibodeau) make a good defensive player (e.g. Deng) into a great one? Or, is the impact limited to making bad defensive players (e.g. Skiles on Monta Ellis) into average ones? Perhaps each player has a physical limit on their defensive abilities, and the best coaching cannot improve a player beyond this point? Or, is coaching defense more about system and tactics, instead of improving individual effort. Any thoughts?