field goals came up because I have been wondering about how to

account for assists in something like an offensive rating or PER

ratings. But in this post I am wondering how much of a possession

an assist should be worth.

Suppose that Jason Kidd came down on 10 straight possessions and

each time he passed off the ball for what would have been an assist

if all 10 field goals had been made. (Assume also that there are no

turnovers and no offensive rebounds.) Suppose the outcomes are as

follows.

3 three point field goals attempted, one successful

4 two point field goals attempted without fouls, one successful

3 two point field goals attempted with fouls, one field goal

successful, three of five free throws successful

In these 10 possessions Jason Kidd would be credited with 3

assists.

John Hollinger would calculate his usage rate as 3*0.67/10 or about

20 percent.

Dean Oliver would calculate his possession usage as 0.5*3*(10-3)/

(2*8) or about 6.6 percent. (This seems like it has to be wrong, so

I must be applying the formula wrong.)

So what is the appropriate possession usage (or usage rate) here? I

don't really know, but both of these seem to me to be giving Jason

Kidd too little credit. To me it would seem that giving Kidd credit

for 33 to 50 percent of these 10 possessions seems more appropriate.

Since I think I might be misapplying Dean's assist formula, I will

only discuss John's in more detail. I think the problem with John's

formula is two-fold.

First, it assumes that free throws are never "assisted." To me it

would seem more reasonable to assume that if Jason Kidd assists 20

percent of his teams field goals, he also assists 20 percent of

their free throws. Assuming that he assists 0 percent of their free

throws seems a bit unfair.

Second, he gets less credit for throwing six passes to Player A who

makes two out of six 22-footers than to Player B who makes three out

of six 19-footers. It would seem to me that he should get the same

credit for passing to these two players, since their true shooting

percentage is the same.

One solution to all of this would be to assume that if Jason Kidd

assists on 20 percent of his team's field goals made, he assists on

20 percent of his team's true field goal attempts. Then if we gave

him one third (or one half) of the credit for assisting on a true

field goal attempt, he would use 33 (or 50) percent of the 10

possessions above.

Now if we found like Ed that the true field goal percentage was

higher on assisted field goal attempts, then we might want to

slightly lower the percentage of true field goal attempts he is

assisting on, but the logic would still be about the same.