APBRmetrics

DSMok1 wrote:That's certainly something to consider. I don't know who you'd give the credit to, though. Probably all of the credit should be to the offensive rebounder/whoever puts it back in, since they are the ones creating the marginal value above league average, not the one shooting it.

Of course, if you've got really good offensive rebounders, you might be inclined to take more low percentage shots from the outside?

On the other, hand possession START numbers should definitely be adjusting the value of the offensive production after it, in my opinion. So--after a steal, the expected points are 1.27. So whoever got the steal (and some credit to other teammates) should definitely get credit for that 1.27 - 1.0X, whatever the average offensive possession is.

One note about the value of a missed shot - it's contextual, since you're right that creating offensive rebounding opportunities depends on who your actual offensive rebounders are!

From this year, the Kings led the league in ORB (didn't realize this) @ 29.9. (That's actually slightly incorrect, since I think Bref uses all possible rebounding opportunities, rather than splicing out shots on FT misses, and here we're dealing with creating shots in the halfcourt, so your halfcourt ORB% is the more important number to use) Contrast that to the Celtics, who had a 21.1, by far the lowest ORB% in the league.

A shot creator who creates shots without turning over the ball in a Kings game provides ~.33 points off a miss (the value of a possession after a rebound x ORB%; again, this number is higher since in a halfcourt setting the Kings rebounding numbers are better) but just ~.23 in a Celtics game. That's a pretty sizable difference, although we are dealing with the 2 extremes here.

Also:

So whoever got the steal (and some credit to other teammates) should definitely get credit for that 1.27 - 1.0X, whatever the average offensive possession is

Right, the value in creating a steal is creating a more favorable possession for the team, so it should be +.2 or whatever... But this also completely disregards the main point of a steal, which is it takes away a +1.1 possession or whatever from your opposition and turns it into a +0 possession for that team. So in isolation a forced live ball TO is worth +1.3 or whatever.

Bobbofitos wrote:

So whoever got the steal (and some credit to other teammates) should definitely get credit for that 1.27 - 1.0X, whatever the average offensive possession is

Right, the value in creating a steal is creating a more favorable possession for the team, so it should be +.2 or whatever... But this also completely disregards the main point of a steal, which is it takes away a +1.1 possession or whatever from your opposition and turns it into a +0 possession for that team. So in isolation a forced live ball TO is worth +1.3 or whatever.

Just to follow this through, it's interesting to think about if you get a steal and then a layup. You would get, say, 1.1 pts for the possession, ~0.16 points for improving the EV of the subsequent possession, and (2-1.27)=0.73 points for making the layup. In other words, you would get (1.1+0.16+0.73)=2 points (more or less). Makes sense to me.

What if you miss the layup? I have to think about that one some more.

This discussion is morphing into what I consider the perfect pbp-based (stat-based) statistic: a sort of "state-based" plus/minus.

Just to follow this through, it's interesting to think about if you get a steal and then a layup. You would get, say, 1.1 pts for the possession, ~0.16 points for improving the EV of the subsequent possession, and (2-1.27)=0.73 points for making the layup. In other words, you would get (1.1+0.16+0.73)=2 points (more or less). Makes sense to me.

What if you miss the layup? I have to think about that one some more.

If you miss the layup, the player who missed and the rest of the team (some sort of credit goes to the other players playing on offense at the same time; perhaps more to the PG--more research needed) should bear the -1.27 of credit.

Part of the advantage of the "SportVU" data is that with such a set of data, more "states" could be detected, and value assigned to, say, a player drawing the defense in on a drive, or to a defensive player causing an opponent to take a tough shot.

I think Jerry's Sloan paper this year involved states like this. Maybe he'll chime in...

EvanZ wrote:I think Jerry's Sloan paper this year involved states like this. Maybe he'll chime in...

I read that the first 3 times through as "Jerry Sloan's paper" and was rather confused!

Yeah, no kidding. I just realized that myself.

Well, Jerry Sloan certainly has more time on his hand these days. He could pop in and say hello, I suppose.

EvanZ wrote:

Bobbofitos wrote:

So whoever got the steal (and some credit to other teammates) should definitely get credit for that 1.27 - 1.0X, whatever the average offensive possession is

Right, the value in creating a steal is creating a more favorable possession for the team, so it should be +.2 or whatever... But this also completely disregards the main point of a steal, which is it takes away a +1.1 possession or whatever from your opposition and turns it into a +0 possession for that team. So in isolation a forced live ball TO is worth +1.3 or whatever.

Just to follow this through, it's interesting to think about if you get a steal and then a layup. You would get, say, 1.1 pts for the possession, ~0.16 points for improving the EV of the subsequent possession, and (2-1.27)=0.73 points for making the layup. In other words, you would get (1.1+0.16+0.73)=2 points (more or less). Makes sense to me.

What if you miss the layup? I have to think about that one some more.

Missing the layup is still a productive play, since you've turned their average possession into a live ball turnover possession for your team (1.3 swing). The 2nd step is your live ball turnover turns into an offensive rebound opportunity, so in a vacuum (without knowing whether it's rebounded by your team or not) it's still worth ~.35. So the EV change is from +~1.2 to +.35, or a net loss of like -.85. Since you've already "gained" 1.3, the net result is like +.45.

DSMok1 wrote:

EvanZ wrote:I think Jerry's Sloan paper this year involved states like this. Maybe he'll chime in...

I read that the first 3 times through as "Jerry Sloan's paper" and was rather confused!

Yeah, considering he doesn't own a computer, he must be quite the math genius!

Probably all of the credit should be to the offensive rebounder/whoever puts it back in, since they are the ones creating the marginal value above league average, not the one shooting it.

What about the guy giving the assist on the second shot? Crossvalidation is everything here. If the original shooter really should not get any credit, it will show in the numbers.

What if you miss the layup? I have to think about that one some more

I never gave any credit when there were no points scored following the action that got you an additional shot. But that was simply a desgin decision. One can/should definitely try to handle things differently. The good thing about doing it my way was that one could see who created "good" steals

If you miss the layup, the player who missed and the rest of the team (some sort of credit goes to the other players playing on offense at the same time; perhaps more to the PG--more research needed) should bear the -1.27 of credit.

Don't forget defense. Maybe the player who blocked the layup should get some positive credit, too. There's a positive and a negative side for pretty much everything.
If there's a steal you want to give negative credit to the guy who turned it over. Just keep in mind that in the end
(the sum of credit for players of team A) - (sum of credit for players of team B) == Points for team A - Points for team B
should hold true

Some of it is in the paper
http://www.sloansportsconference.com/wp ... iation.pdf

J.E. wrote: Don't forget defense. Maybe the player who blocked the layup should get some positive credit, too. There's a positive and a negative side for pretty much everything.
If there's a steal you want to give negative credit to the guy who turned it over. Just keep in mind that in the end
(the sum of credit for players of team A) - (sum of credit for players of team B) == Points for team A - Points for team B
should hold true

Of course--I should have put that in there. I would, for simplicity's sake, always divide credit between offense and defense equally.