A while back I used 2002-2012 PI RAPM data to quantify differences in the “supporting casts” that surround a star player. The results were largely what we’d expect: That the players who surround a star (including other all-stars themselves) are hugely important in determining a team’s performance.

In the chart below I’ve graphed a team’s best player and his support based on how far they advanced in a season. I’ve also included min/max ranges for the supporting casts based on the data:

The data reflects common sense. As teams grow better, the players surrounding the star grow better. Improvements to the star himself are correlated with more team success, but the supporting players on a team are more important to the team’s success than the star player. This is expected; basketball is not a one-on-one sport. Still, it’s nice to be able to quantify this with a decade of non-box score data.

The importance of supporting casts can be seen most clearly in the correlations. The correlation between the entire team’s individual RAPM values and its Margin of Victory (MOV) is nearly perfect (0.95). The correlation between the “supporting cast’s” RAPM and MOV is 0.91, but the correlation with a best player’s RAPM is only 0.68. So if we removed the star player from every team in the league, we could still reasonably predict who the best teams were based on the performance of the other players. We could not make this prediction by only looking at the stars themselves.

Graphically, we can see the relative lack of relationship between the top player and team MOV compared to the strong relationship between the supporting players and team MOV:

Finally, note the vast disparity in supporting cast among non-playoff teams. The floor for a playoff team and the floor for a non-playoff team are separated by 10 points! Literally, off the chart.

Methodology

“Best Player” is defined by the player with best minute-weighted RAPM for a team for a season. For example, if Player A has +5 RAPM and Player B a +4 RAPM but Player B plays 100% of the minutes and Player A 50% of the team minutes, Player B is credited with a “4” lift to the team and is thus considered their best player. (B would have a +2.5 lift).

“Supporting Cast” is defined by the minute-weighted totals of all other players on the team, summed together.

For traded players, the total season RAPM value was used

For minute-weighted totals, only players with 300 MP were considered

Specific Players

I’m always asked for notable players across a period, so this is how they shook out based on this metric. First players with at least 3 seasons as the “top player.” The second table has all players.

Player Avg. Min Max 2002 03 04 05 06 07 08 09 10 11 12 Dirk Nowitzki 1.0 -2.2 3.5 0.1 3.1 0.2 2.5 1.2 3.5 0.4 0.8 0.4 -2.2 Kevin Garnett -0.4 -7.8 5.3 0.1 -0.6 -0.2 -1.0 -5.2 -7.8 3.9 5.3 2.2 -1.0 Tim Duncan 2.4 0.7 3.4 3.4 3.0 2.7 1.8 2.7 0.7 2.0 2.0 3.2 LeBron James 0.1 -4.0 3.0 0.9 -1.8 -1.7 -4.0 2.6 -0.4 3.0 2.4 Luol Deng -0.3 -4.5 4.3 -1.1 -1.6 1.5 -4.5 -2.9 2.5 4.3 Steve Nash -0.1 -3.5 4.2 0.2 4.2 0.6 -0.8 1.8 -3.5 -3.0 Baron Davis -1.7 -3.0 0.9 -0.5 0.9 -3.0 -2.7 -2.6 -2.0 Dwight Howard -0.1 -4.5 3.7 -4.5 -1.5 2.2 3.7 0.4 -1.0 Elton Brand -2.2 -4.8 -0.3 -3.8 -0.3 -1.1 -2.2 -4.8 -0.9 Jason Kidd 0.3 -2.5 3.3 2.4 3.3 -0.2 -1.5 -2.5 0.1 Kobe Bryant -0.1 -3.7 4.5 -2.7 -1.7 -3.7 1.3 4.5 1.6 Brad Miller -3.2 -8.3 0.0 0.0 -1.2 -2.3 -4.2 -8.3 Dwyane Wade -4.5 -9.6 -0.9 -0.9 -3.6 -9.6 -4.0 -4.5 LaMarcus Aldridge -0.4 -2.9 2.6 -2.9 2.6 0.4 -0.5 -1.5 Rasheed Wallace 0.1 -1.4 2.6 -0.4 0.9 -1.4 2.6 -1.1 Andrei Kirilenko -1.1 -6.4 2.8 -1.9 -6.4 2.8 1.2 Chris Bosh -2.6 -3.8 -1.6 -1.8 -1.6 -3.8 -3.2 Chris Paul -2.5 -3.6 -0.5 -2.7 -3.3 -3.6 -0.5 Gerald Wallace -3.9 -6.6 -0.3 -6.2 -2.4 -0.3 -6.6 Josh Smith -2.7 -7.2 1.2 -7.2 1.2 -2.9 -1.8 Paul Pierce -3.0 -5.4 -1.5 -1.7 -1.5 -3.6 -5.4 Ray Allen -1.8 -6.0 2.6 -5.0 1.1 -6.0 2.6 Shaquille O'Neal 1.4 -0.1 3.2 1.4 1.0 -0.1 3.2 Shawn Marion -0.9 -3.1 1.8 -3.1 0.5 -3.0 1.8 Steve Francis -2.3 -4.7 -1.0 -4.7 -1.2 -1.0 -2.4 Allen Iverson -1.7 -3.9 -0.4 -0.9 -3.9 -0.4 Andrew Bogut -2.7 -3.4 -2.2 -2.2 -2.3 -3.4 Antawn Jamison -4.4 -7.2 -1.3 -1.3 -4.6 -7.2 Ben Wallace -2.0 -6.4 3.0 -2.4 3.0 -6.4 Bobby Simmons -5.4 -9.2 -3.0 -4.1 -3.0 -9.2 Brendan Haywood -4.9 -6.8 -1.7 -6.8 -1.7 -6.2 Carlos Boozer -0.4 -1.7 2.3 -1.7 -1.6 2.3 Chauncey Billups 3.0 2.5 3.7 2.7 3.7 2.5 Danny Granger -2.3 -5.4 -0.1 -1.5 -5.4 -0.1 Jermaine O'Neal -1.2 -4.0 1.7 -1.2 1.7 -4.0 Kevin Durant 1.6 0.1 4.0 0.1 0.8 4.0 Marcus Camby -5.9 -9.6 -0.9 -0.9 -9.6 -7.2 Metta World Peace -2.9 -6.4 1.1 -6.4 1.1 -3.5 Nene Hilario 0.5 -1.5 1.9 -1.5 1.9 1.1 Pau Gasol -1.1 -8.1 4.1 -8.1 4.1 0.7 Rashard Lewis -2.8 -8.6 3.7 -3.5 3.7 -8.6 Shane Battier -0.2 -1.3 0.9 0.9 -0.3 -1.3 Theo Ratliff -6.6 -9.7 -4.1 -4.1 -6.0 -9.7 Vince Carter -7.2 -7.2 -7.1 -7.2 -7.2 -7.1