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Re: Toronto Raptors using SportsVU
Posted: Thu Mar 21, 2013 1:30 pm
by Mike G
Is that a problem with WS/48 or a truism--when a player plays better, his team will be better?
You can swap 2 identical players between a good team and a bad team.
The teams will still be just as good/bad, and the players' WS/48 will flip.
Here's an example, not of identical players, but PG's Jason Williams and Mike Bibby, who were swapped in 2001/2002.
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year JWill tmW% PER WS/48
2001 Kings .70 12.8 .079
2002 Grizz .24 15.1 .020
year Bibby tmW% PER WS/48
2001 Grizz .30 16.8 .081
2002 Kings .74 14.9 .113
PER, for corroboration purposes, says the players were better (more productive?) with their poorer teams.
WS/48 says the opposite.
I've used pythagorean W% for the teams.
Re: Toronto Raptors using SportsVU
Posted: Thu Mar 21, 2013 2:59 pm
by deepak
DSMok1 wrote:Mike G wrote:A given player will almost always have higher WS/48 with a better team.
Is that a problem with WS/48 or a truism--when a player plays better, his team will be better?
I think, in general, the issue here is that WS, being based on DRTG, is dependent on team defense. If a player goes to a significantly better or worse defensive team, his DRTG will correspondingly change.
Though for Rudy Gay's case, his drop in WS/48 can just as well be explained by his drop in offensive efficiency.
Re: Toronto Raptors using SportsVU
Posted: Thu Mar 21, 2013 3:56 pm
by xkonk
I mentioned 'quick and dirty'. Any non-WS measures that could better inform the issue? Also, the team quality issue doesn't apply to Calderon, who appears to be playing better on a worse team.
Re: Toronto Raptors using SportsVU
Posted: Thu Mar 28, 2013 12:31 pm
by Mike G
Win Shares will better predict players' and teams' win rates after this conversion:
WS2 = WS/48 + (.500 - pyth%)*.17
... where pyth% is the team's pythagorean W%, based on point differential.
This adjustment works to remove the 'exaggeration' of players' WS rate due to team excellence/suckiness.
For players on a .600 pyth% team, the formula suggests subtracting .017 from their WS/48.
For teams at the extremes, the adjustment is more profound: Players from last year's historically bad Bobcats get .063 added to their WS/48 rates.
DJ Augustin therefore goes from .018 to .081 -- from abysmal to respectable.
This year, he's listed at .113 in Indiana. But they're a .600 team, so he's "really" just a .096 player on a .500 team.
Has he improved by .095 WS/48, or by merely .015 ? The latter seems a lot more likely.
With this new WS/48 applied, players' WS will not add up to team wins (or pyth wins). You have to un-convert: Multiply by 1.17*(Pyth% - .500) to get "expected" team wins.
Of 223 players with at least 500 minutes both last year and this year, 60% are closer to last year's WS/48 after conversion.
The average change in WS/48 is .033, and after adjustment it's .027
Re: Toronto Raptors using SportsVU
Posted: Sun Mar 31, 2013 10:45 am
by Mike G
I did this a few weeks ago, so the 2013 team and player rates have changed. Still, for what it's worth, the 30 players with biggest changes in WS/48 rates, last year to this year. Minimum of 500 minutes each season.
Shown are team pythagorean W% , WS/48 rates, and "adjusted" WS/48 for both years. The final column is "improvement" in the change: Less measured change is generally "better"; and the vast majority are less changed after adjustment. Minus sign indicates a bigger change.
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.Win Shares 2011-12 2012-13 Win Shares/48 Adjusted WS/48
.most changed Tm pyth% Tm pyth% 2012 2013 2012 2013 diff
Andray Blatche WAS .342 BRK .515 -.011 .160 .016 .157 .029
Kevin Love MIN .426 MIN .392 .223 .096 .236 .114 .006
Greg Stiemsma BOS .585 MIN .392 .170 .044 .156 .062 .033
Toney Douglas NYK .602 HOU .585 -.046 .075 -.063 .061 -.003
Kevin Seraphin WAS .342 WAS .363 .094 -.014 .121 .009 -.004
Brendan Haywood DAL .529 CHA .231 .114 .011 .109 .057 .051
Marvin Williams ATL .611 UTA .487 .156 .053 .137 .055 .021
Will Bynum DET .338 DET .440 -.023 .078 .005 .088 .017
D.J. Augustin CHA .128 IND .600 .018 .113 .081 .096 .080
Andrea Bargnani TOR .384 TOR .452 .104 .009 .124 .017 -.012
.Win Shares 2011-12 2012-13 Win Shares/48 Adjusted WS/48
DeShawn Stevenson NJN .307 ATL .524 -.014 .080 .019 .076 .037
James Johnson TOR .384 SAC .284 .079 -.014 .099 .023 .017
Larry Sanders MIL .506 MIL .462 .072 .158 .071 .164 -.007
Joakim Noah CHI .754 CHI .552 .223 .139 .180 .130 .034
Luc Mbah a Moute MIL .506 MIL .462 .112 .031 .111 .037 .007
Kemba Walker CHA .128 CHA .231 .009 .087 .072 .133 .018
Andre Iguodala PHI .641 DEN .609 .158 .081 .134 .062 .005
Marcin Gortat PHO .489 PHO .326 .172 .095 .174 .125 .028
Dirk Nowitzki DAL .529 DAL .452 .175 .098 .170 .106 .013
Martell Webster MIN .426 WAS .363 .064 .140 .077 .163 -.011
.Win Shares 2011-12 2012-13 Win Shares/48 Adjusted WS/48
Ryan Anderson ORL .524 NOH .396 .219 .145 .215 .163 .022
Gustavo Ayon NOH .368 ORL .324 .142 .068 .164 .098 .007
Earl Clark ORL .524 LAL .520 .027 .100 .023 .097 -.001
Spencer Hawes PHI .641 PHI .391 .152 .081 .128 .100 .043
Kevin Durant OKC .684 OKC .753 .230 .300 .199 .257 .012
Michael Beasley MIN .426 PHO .326 .022 -.047 .035 -.017 .017
Avery Bradley BOS .585 BOS .498 .085 .016 .071 .016 .015
Arron Afflalo DEN .586 ORL .324 .121 .052 .106 .082 .045
Carlos Boozer CHI .754 CHI .552 .187 .118 .144 .109 .034
Rodney Stuckey DET .338 DET .440 .131 .063 .159 .073 -.017
On average, 2012 to 2013 WS/48 differences are lessened by .018 in this group.
Beasley is the only player of 223 who carries a negative Adj WS/48 this year. Only 8 are below .020
Re: Toronto Raptors using SportsVU
Posted: Mon Apr 01, 2013 4:39 pm
by xkonk
Does it make sense to include players who haven't changed teams in an analysis like this? Kevin Love, for example, gets his rating bumped up because the Wolves are playing worse this year than last year. But certainly that's due in part to the fact that Love has missed time and played injured. Should he get credit for a decrease in team performance that is at least partly his 'fault'?
Re: Toronto Raptors using SportsVU
Posted: Mon Apr 01, 2013 9:42 pm
by Mike G
Good question. After adjustment, the formula asserts that last year his .426 Wolves dragged his personal WS/48 down from .236 to .223. And this year, the .392 mark has depressed it from .114 to .096 .
Code: Select all
.Win Shares 2011-12 2012-13 Win Shares/48 Adjusted WS/48
.most changed Tm pyth% Tm pyth% 2012 2013 2012 2013 diff
Andray Blatche WAS .342 BRK .515 -.011 .160 .016 .157 .029
Kevin Love MIN .426 MIN .392 .223 .096 .236 .114 .006
The depressive effect of his weak team has increased from .013 to .018, last year to this year.
Or conversely, the adjustment is slightly bigger this year, to gauge what he'd be with a .500 team.
The .018 bump-up is a small rebate on the .127 dropoff WS/48 has measured.
The Nets, meanwhile have improved from .307 to .515 . Their average player, therefore, would be .061 last year and .103 this year. These are just 1/5 of the team pyth%
Deron Williams' WS/48 has gone from .099 to .140 . After adjustment, it's from .132 to .137
Kris Humphries' WS/48 has gone from .118 to .112. Adjusted, it's .151 to .109
Is DWill greatly improved and Humphries slightly diminished?
Or is DWill slightly up and Humphries way off his game?