How can we evaluate NBA players? We can look at box scores, but much of the NBA game (especially defense) is not captured by the box score. It seems obvious that defense and offense play equal roles in determining a team’s success. My colleague, Jeff Sagarin, and I prefer to look at how each player moves the score of the game. When good players are in their team tends to do well and when good players are out, their team tends to do poorly. This type of system gives equal weight to a player (or lineup’s) offensive and defensive abilities. Using fairly sophisticated mathematical techniques we can find ratings for players and lineup combinations that best explain the movement of the scores in each NBA game. The key idea in rating players is to adjust performance based on who you play with and who you play against. For example, losing to the Celtic’s starting lineup by 5 points in 48 minutes is a better performance that beating the Knicks starting lineup by 5 points in 48 minutes. We can also rate lineup combinations. For more details on our methods see Chapter 40 of my new book Mathletics.
Even though the NBA season is less than three weeks old, our methods give us many interesting insights into player, lineup and team performance. All numbers below are based on games through November 12, 2009. All numbers below are per 48 minutes and adjusted based on strength of opponents.
Who’s best so Far?
The Celtics have been by far the league’s best team. After adjusting for the strength of their opponents, we find the Celtics have played 14 points better than an average team. The amazing thing about the Celtics is that just about any lineup they put on the court has been great. Unsurprisingly, when the Big 4 of KG, Ray Allen, Rondo and Pierce is on the court the Celtics play 17 points better (per 48 minutes) than an average team. The amazing thing is the rest of the time the Celtics play 11 points better than average. With their deep bench (and Big Baby has not played yet) the Celtics are best positioned to withstand an injury to a star player.
Should Byron Scott have been fired?
The Hornets have played poorly so far (9 points worse than average). This level of performance would never lead to a playoff berth. When the Hornet’s Big 3 of Peja, West and Paul is in the Hornets are fine (11 points better than average). The problem is the rest of the time the Hornets play an abysmal 18 points worse than average. This indicates the rest of the roster is weak. Should the blame for CP3’s weak supporting cast fall on Scott or GM Jeff Bower? Since Bower is the new coach, the answer should soon be apparent.
How about those Amazing Bucks?
Before the season started, virtually nobody thought the Bucks had a shot at making the playoffs. So far the Bucks have played 5 points better than average. If this level of play continues they will make some noise in the playoffs. Brandon Jennings is our early pick for rookie of the year. After adjusting for strength of opponents and teammate’s ability he has played 22 points better than an average player. When Jennings is on the court the Bucks play 12 points better than average and when he is off the court the Bucks play 10 points worse than average. When the quartet of Bell, Bogut, Jennings, and Delfino is on the court the Bucks play an amazing 35 points better than average. Props to coach Scott Skiles for a great job!
The Fountain of Youth Has Moved to Auburn Hills!
Last year Ben Wallace broke his leg and struggled with the Cavs. In fact, against the Magic when Ben and LeBron were in together the Cavs lost by 58 points in 57 minutes! This year, however, Ben has returned to the Pistons and coming back to his former team has enabled him to capture the skills that won him several Defensive Player of the year honors. When Wallace is on the court the Pistons give up 15 points per game less than they would if an average NBA defender took his place. Ben Gordon and Rodney Stuckey have also keyed the Piston’s resurgence. When Wallace, Gordon and Stuckey are in together the Pistons play 17 points better than average. By the way when Gordon is out the Pistons play 20 points worse than average.
Will the Lakers Repeat?
At this writing, the Lakers sit atop the Western Conference with a 7-1 record. They have achieved this mark without one of last year’s top players, Paul Gasol. Still, all is not right in Hollywood After adjusting for opponent’s strength the Lakers have played only 3 points better than average. When Artest and Bryant are in together the Lakers are awesome: 21 points better than average. But when Artest and Bryant are not both in the Lakers are woeful: 24 points worse than average. Even if Gasol comes back at full strength, I have trouble seeing how the Lakers can compete with the Celtics. I would not be surprised if another team represents the West this year in the NBA finals.
Are the Suns for Real?
At this writing the Suns are 8-2 and the talk of the league. Despite their gaudy record, the Suns have played only 3 points better than average. When their schedule gets more difficult, expect their record to drop off.
Can the Knicks be fixed?
The Knicks are off to a miserable 1-8 start. The main problem is that when Duhon. Lee and Chandler are in the game the Knicks play 11 points worse than average. The two bright spots for the Knicks have been Gallinari’s great offense and Hughes’ great defense. When the trio of Hughes, Gallo, and Harrington are in the Knicks play 19 points better than average. When Nate Robinson returns I would start Nate with this trio and I think the Knicks performance would greatly improve. To find more details on the Knicks check out my post on waynewinston.com.
That’s all the space we have. Next week we will look at other burning questions such as how is the Shaq/LeBron experiment working out in Cleveland?