Wednesday, March 16, 2011

The myth of the Derrick Rose keystone

In architecture the keystone is the wedge-shaped piece that holds the stones together. Without the keystone the entire arch collapses and is just a pile of rubble. Why the architecture lesson? Well maybe people try to make this argument about the 2011 Chicago Bulls regarding Derrick Rose.

The argument goes "Without Derrick Rose, the Chicago Bulls collapse and aren't near the team they are with him."

I hear this argument a ton from Bulls fans. I've lived in Chicago. Yes, I know a lot of Bulls fans. Unfortunately for those making the argument, the facts just don't bare out that particular claim. Let's look at some numbers. (taken from Queen City Hoops on 3/16/11)

Now this might be hard for some believe, but look at those numbers it's hard to see how the Bulls collapse without Derrick Rose as their PG. Sure they aren't a top seed in the East, but their net differential when he doesn't play is +1.8, which projects out to a 46-36 record. That's a .561 winning percentage, which would be good enough for the 6th seed in the East right now. Not exactly a ringing endorsement for the Bulls "collapsing."

Okay, well that's net differential. Let's look at a different data set. How about Wins Produced? Surely that metric will show Rose being the keystone to the Bulls. (data powered by NerdNumbers)

Okay so here we see that Rose has had a pretty good season. .182 WP48 means he's producing at a star level in the NBA (>.200 is star level; >.300 is superstar) (Yes, I realize he only has .182 and star is supposed to be .200, but that's within the margin of error.) He's also produced the most wins for the Bulls, but that's a little misleading since he's played twice as many minutes as Noah, who's the real wins producer on this team. Rose has produced 19.7% of this teams wins so far. If we project that out to an 82 game season that's 16 wins. That's pretty good. Okay, now let's project out the teams current win percentage of 72.7% to 82 games, which is 60 games. 60-16 = 44. So by the Wins Produced metric, the Bulls would be roughly 44-38. That's a winning percentage of 53.6%, which would be good enough, again, for the 6th seed in the East.

Now that's two different ways of looking at this. And wouldn't you know it both show Derrick Rose having about the same effect on the Bulls. Both say that they'd still be the 6th seed in the East this season with him. And both show that the Bulls wouldn't collapse without Derrick Rose on their team. That is all.

The Rose argument isn't as structurally sounds as this...

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