Offensive Rebounding vs. Getting Back on Defense

[mystic]

I was a bit surprised by this finding. It implies that the variance in ORB% is much larger than the variance in DRB%. I had thought they were roughly similar at the team level. Is the variance in DRB% much smaller? Any thoughts on why that is?

Indeed, the ORB_dif has a 2.4, and DRB_dif has 1.8. I suspect that the bigger variance for the ORB% is partly caused by differences in strategies regarding "crashing the offensive board" and "getting back on defense".

[Guy]

So, in order to check that, we can adjust the DRB-ORB by using the opponent eFG% as predictor for the expected DRB% here. I use league average eFG% - opponents eFG% = eFG%_dif. Then I ran a linear regression and found that 0.576*eFG%_dif = DRB_dif. I use that to determine an expected DRB%, which is then used to adjust DRB-ORB.

For the 235 cases, which have a bigger than 1 sigma difference I found: R²=0.180, p-value = 0.000.

If you would be correct, we shouldn't see a statistical significant correlation.

I confess I don't follow what you did here. But why not simply replace Def Rtg with opponent eFG% in your analysis? Wouldn't that be a much cleaner approach? If they tradeoff exists, I would think it would be apparent in opponents' shooting efficiency. And the benefit is that you are then no longer in the tautology business....

[mystic]

I confess I don't follow what you did here. But why not simply replace Def Rtg with opponent eFG% in your analysis? Wouldn't that be a much cleaner approach? If they tradeoff exists, I would think it would be apparent in opponents' shooting efficiency. And the benefit is that you are then no longer in the tautology business....

Well, you suggested a big correlation between opponents eFG% and DRB%, implying that a lower eFG% should automatically lead to a higher DRB%. So, in order to reduce the influence of that effect, I used the opponents eFG% as a proxy for the expected DRB%. Then I reduced the DRB-ORB value by the expected DRB%, in that way I should have eliminated the bias introduced by the opponents eFG%.

But I can do what you suggests, the result would be: R²=0.110, p-value=0.000

So, there is obviously a tradeoff effect here.