APBRmetrics

I have a question about calculations in Wins Produced

http://wagesofwins.com/how-to-calculate-wins-produced/

For example, Derrick Rose committed 8.2% of Chicago’s personal fouls in 2010-11. Chicago’s opponents made 1,450 free throws, so Rose is charged with 119.5FTM(opp.).

8,2%?

Derrick Rose had 136 fouls
Chicago had 1639 fouls
so... 136/1639 is 8,297% ~ 8,3%

next...

Rose PROD= 128*0.064 + 583*0.032 + 476*0.017 + 886*-0.034 + 79*-0.015 + 81*0.034 + 249*0.034 + 278*-0.034 + 85*0.033 + 119.5*-0.017 + 51*0.020 = 7.47

equation '128*0.064 + 583*0.032 + 476*0.017 + 886*-0.034 + 79*-0.015 + 81*0.034 + 249*0.034 + 278*-0.034 + 85*0.033 + 119.5*-0.017 + 51*0.020' give us 7,1925 ~ 7,19

where is the error?
who did it wrong?

My guess would be from the part directly between the general equation and Rose's specific numbers:

NOTE: One should note that the above values have been rounded off to three decimals. The results reported below for each player were ascertained without any rounding.

Your numbers are right, and it's also true that the calculations on that page are done with non-rounded numbers. Be careful though, there are quite a few errors on that page...

Ok, but if we have:

Derrick Rose had 136 fouls
Chicago had 1639 fouls
so... 136/1639 is 8,297% ~ 8,3%

we cant use 8.3 instead of 8.2 in next steps, because this is first step and later we will have different result and that difference will be big

I looked at the further calculations and...

Bulls Team Defensive Adjustment = [(427*-0.064 + 2378*-0.032 + 567*0.033 + 57*-0.034 + 415.0*0.033 – 468*0.200)/19,830]*48 = -0.195

-0,195?!

This is no longer a matter of the adopted approximations. Good result is -0,40316 !

So if every result on that site is bad, it is so strage, that Wins Produced are so popular...

Popular?

I thought so..

It is very popular amongst what I'd describe as the pseudo-science crowd. Guys who have degrees/high school level scientific understanding but whose understanding of regression analysis is extremely meagre. The biggest single issue with Wins Produced (other than the constant use of straw men/appeals to scientific authority in answering criticism) is that it takes a team-level regression and assumes it will correctly apportion credit/blame at the player level. Good examples of this on defence are the fact that a DRB is worth half a defensive stop (madness!) and that a foul should be penalized with the full value of foul shots made as a result (very dumb).

JohnQ wrote:I have a question about calculations in Wins Produced

http://wagesofwins.com/how-to-calculate-wins-produced/

where is the error?

The day some book editor said "sure, we'll publish that book".

There are other threads where Wins Produced is discussed... I don't think we need another one. Could we please stay on topic here? Thanks!

I think it's good to point out that Wins Produced is a bad metric beyond the inaccuracy of that particular page. WoW is a dangerous honey trap for people interested in getting into basketball stats who might be fooled by its following/the arrogance of Berri.

This post is not intended to patronize, unfortunately the letters PHD are far too convincing in a 'he has a PHD so he must be right' kind of way.