APBRmetrics

ziller · Joined: 30 Jun 2005 Posts: 118 Location: Sac Metro

I did a cursory search and couldn't find anything, so here's a question for those involved in calculating VORP:

I got 0.455 for the replacement level this year using Kevin's formula. Anyone think that's high? It's been that high in the past, but several hundredths lower recently.

That high number has also served to seemingly undervalue the superstars. Only Amare rated over 400 (420 by my calculations), and Garnett came in with 380. Tim Duncan really got hurt by missing games, and finished 19, one spot behind Nash.

Adjusting the replacement level to 0.450 puts Garnett at 404 and Amare at 430. But Nowitzki finishes third with that, seemingly low at 370.

What is everyone else using as the replacement level value?
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Kevin Pelton · Posted: Wed Jul 20, 2005 9:08 pm Post subject:

I don't think anyone else really does VORP, at least not here.

When I go through my methodology, I get Keith Bogans (efficiency .434) as the 300th-rated player, which is where I'd set replacement level (rounding to .435). That produces the following VORP leaderboard:

jkubatko · Joined: 05 Jan 2005 Posts: 508 Location: Columbus, OH

Mike G · Joined: 14 Jan 2005 Posts: 1506 Location: Delphi, Indiana

I've got 398 players who appeared last season and contributed net + eWins. Very-near zero on the scale are Geno Carlisle, Pig Miller, Yuta Tabuse, Jahidi White, Damone Brown, Tony Bobbitt, Darrick Martin, Brandin Knight, Kedrick Brown, Torraye Braggs, Maciej Lampe.

Only about 80 came in at less than zero. I guess these could be called replacement-hopefuls who could not even compete effectively against replacements.

398/30 is just about 13 per team. That seems pretty lenient, in a year when there weren't a terrible number of injuries. But the production level equal to no-wins-contributed was determined by the closest correlation to team wins.

Kevin Pelton · Posted: Wed Jul 20, 2005 10:15 pm Post subject:

ziller · Joined: 30 Jun 2005 Posts: 118 Location: Sac Metro

jkubatko · Joined: 05 Jan 2005 Posts: 508 Location: Columbus, OH

Kevin Pelton · Posted: Thu Jul 21, 2005 2:14 pm Post subject:

Ah, that makes sense. Yeah, you have to filter out the multi-team players. No fair counting, say, Antoine Walker as three players.

I think you have two separate questions here, one being "Why isn't this specific version of VORP used?" and the other being "Why isn't replacement level used?"

The first is pretty simple. It's a crappy little formula I put together in my dorm room, and JustinK has shown in the past that it doesn't work as well as a linear-weights system as PER (as far as estimating team performance). It isn't in terms of anything, as he points out, and I usually do PER now when I use linear weights.

As to why replacement level theory is pretty rarely used in the NBA, I'm not sure. If you do a win-percentage based system, you can do a WARP rating, which has a tangible "in terms of" wins. But EdK and I are the only ones who have really done much with that, I think.

[Edit to point out MikeG has also implicitly taken this into account with his more recent stuff, I think.]

ziller · Joined: 30 Jun 2005 Posts: 118 Location: Sac Metro

A main reason I ask and a reason I've been looking more into replacement level in the NBA of late is a vast debate in Kings circles about Webber's tenure.

Many say that he actually hurt the team by being on it, citing some stats that show Sacramento's aggregate win percentage since 1999 was better when he wasn't playing than when he was. Some even said that the team would've won a title had Webber disappeared as was replaced by the Kings then back-ups, who were replaced by available replacement-level players.

That doesn't come close to making sense in my head, so I've been looking at a way to really study the phenomenon. Hence, VORP.

I'm going to poke around for more info on WARP. Anything in particular I should read?
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Kevin Pelton · Posted: Thu Jul 21, 2005 2:31 pm Post subject:

http://www.hoopsworld.com/cgi-bin/news/exec/view.cgi?archive=39&num=8638

http://www.sonicscentral.com/ratingsystem.html

ziller · Joined: 30 Jun 2005 Posts: 118 Location: Sac Metro

Incredibly helpful as always, Kevin.
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jkubatko · Joined: 05 Jan 2005 Posts: 508 Location: Columbus, OH

Using Dean Oliver's wins and losses (which can be found on my site), I calculated 2005 VORP using the following formula:

jkubatko · Joined: 05 Jan 2005 Posts: 508 Location: Columbus, OH

Since you were asking about the Kings, here are the best player seasons since the team moved to Sacramento:

ziller · Joined: 30 Jun 2005 Posts: 118 Location: Sac Metro

Thanks Justin! That Doug Christie season is surprising, though his DRating was obviously awesome.
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ziller · Joined: 30 Jun 2005 Posts: 118 Location: Sac Metro

Thanks to the formula (that would be WARP?) and B-Ref, I took off my training wheels and calculated the Wins Above Replacement Level for the 2005 Kings: