Do NBA Coaches Actually Make an Impact?
Here's the good news for the NBA's three first-time head coaches this season: There's very little chance you're going to make your players worse.
Here's the bad news: Chances are slim that you'll make them any better.
In a league where coaching turnover is rampant—almost eight changes per season over the past two decades—a study co-written by Southern Utah University economics professor Dave Berri suggests that fewer than a quarter of NBA coaches between 1977 and 2008 had any significant effect on their players' performance.
Mr. Berri looked at 62 coaches in the three-decade span, only including those who worked long enough to have 15 everyday players come to their team after their arrival, as well as 15 everyday players leave (this was to make sure each coach had a sizable roster of players to analyze). Mr. Berri used his wins-produced metric—which shows how many wins a player is worth by seeing how his statistics correlate to winning—to measure the players' performances and see whether they significantly improved or declined. If they did, then the coach passed the so-called effectiveness test.
Phil Jackson, who has won a record 11 titles, is worth 17.1 wins to his teams per year according to this metric—the most in the sample. But Hall of Famer Pat Riley had no significant effect at all; neither did well-known coaches such as Jeff Van Gundy and Jerry Sloan. Then there's Matt Guokas, who compiled a .430 winning percentage in seven years as head coach. He's the only person in this sample to make his players significantly worse.
The Ones Who Matter
A recent study shows the majority of experienced NBA coaches in the past few decades had no significant effect on their players' performance. Here are some of the well-known exceptions. *
MOST EFFECTIVE COACHES HOW MANY 'WINS' THEY CONTRIBUTE A SEASON Phil Jackson
17.1 Gregg Popovich
15.9 Cotton Fitzsimmons
15.8 Jim O'Brien
12 Gene Shue
11.5 Don Nelson
11.2 Flip Saunders