Posted: Wed May 17, 2006 5:04 pm Post subject: Actual / Projected Stats for the 05-06 Rookie Class
While looking for something else I stumbled across this title
http://www.82games.com/pelton6.htm
and decided to look and see how well Kevin did projecting rookie class stats. I think he did well overall. On about half he was quite close on either everything including minutes or after adjusting hard to predict minutes. On the most of the rest he was low mainly on points but did better on rebounds, assists. Paul and Frye perhaps beat the projection by the most, Bogut was a little short.
Kevin, are you interested in discussing your methods? (there have been a few posts that have shown interest in college to NBA stat translation in recent months) Do you plan any changes to methodology or weighting for the next class of rookies? I assume you plan on waiting until they have been drafted and have gone thru the summer league before posting?
Last edited by Mark on Wed May 17, 2006 7:43 pm; edited 1 time in total
Joined: 13 Oct 2005 Posts: 183 Location: Atlanta, GA
Posted: Wed May 17, 2006 6:04 pm Post subject:
Speaking of which, I projected PER's for rookies here before the season. I have no idea if I did well or not, though (seeing as no one else to my knowledge did projected PER's), but since Mark brought up the topic of rookie projections, I thought I'd chime in...
I did a quick check of about 20 and it looks like you did a good job as well, generally +/- 1-3 on PER. You had Paul at a modest PER15, Frye a little higher at 16 (I didnt make a full set of projections but I was pretty high on him before the draft).
I'll leave it to the two of you to more fully analyze your own results or make side by side comparisons if you want.
Joined: 13 Oct 2005 Posts: 183 Location: Atlanta, GA
Posted: Wed May 17, 2006 7:35 pm Post subject:
I'm sure Kevin's methodology was a lot more scientific than mine. I simply went to the various draft sites (ESPN.com, Hoopshype, NBADraft.net, DraftExpress, etc.) and compiled a list of comparable players, then checked how those comps did at the same age. As you probably know, many of the comps can be outlandish (for example, practically every European SF gets compared to Dirk Nowitzki), so I scaled down as I saw fit, and for those w/o adequate comps I just went on gut instinct. Probably not textbook APBRmetrics, to be sure... If he is interested in posting it, I would love to hear Kevin's methodology as well, as it will likely be of benefit to my "system".
A few comments on a couple of the guys on Kevin's list of 12:
Ray Felton March 17pts 7 assists 4 rebs and good shooting %s
April 17pts 10 assists 3 rebs and terrible shooting %s
his minutes and average more than doubled from November to April.
If he plays those minutes next year he may compete with Paul on glossy offensive numbers. His one on one defense looks better than Paul on counterpart PER especially at SG.
Jarret Jack closed strong in April 12pt 5 assists in 26 minutes and 55%FG.
I expect him to have a strong 2nd year.
Ike Diogu also closed strong with 12 pts 6 rebs in 22 minutes in April. Will they create more playing time for him? I would.
How close does Charlie V get to 20 pts 10 rebs? Based on improvement shown in final months I expect pretty close. Anything less than 17pts 9 rebs would disappoint me.
Deron Williams probably shows some pts /assists improvement and even more on PER. Maybe he gets some better national press too, especially if the Jazz makes playoffs as they probably should.
What happens to Paul's stats depends heavily on what the Hornets and Claxton do about his free agency. If Claxton leaves, Paul get bigger numbers but Hornets chances for the playoffs probably take a step back.
If Paul goes over 20 pts a night he may remain the most talked about but with as his fellow rookies getting closer to the same level of minutes and advance further in their transition (Paul was quickest with this) it will be a more competitive comparison among them.
Kevin projected the following stats:
MPG, PPG, RPG, APG, SPG, BPG, and TOPG, along with some fantasy-style stats that need not concern us. First thing's first: we have MPG, so the other per game stats can be made into per 48 minutes stats to facilitate comparison. Here's how Kevin's projections look:
Code:
MPG PTS REB AST STL BLK TO
Actual Pelton Actual Pelton Actual Pelton Actual Pelton Actual Pelton Actual Pelton Actual Pelton
Andrew Bogut 29 30 15.7 18.4 11.7 13.1 3.9 3.2 1.0 1.1 1.4 2.1 2.6 3.0
Chris Paul 36 28 21.5 13.9 6.8 5.1 10.4 9.4 3.0 2.7 0.1 0.0 3.1 3.3
Marvin Williams 25 28 16.5 15.3 9.4 11.0 1.5 1.5 1.2 1.9 0.6 0.9 2.0 2.7
Channing Frye 24 18 24.5 16.0 11.4 9.3 1.6 2.9 0.9 1.3 1.4 2.7 3.0 2.1
Jarrett Jack 20 20 15.8 14.2 4.8 5.3 6.6 6.2 1.2 2.2 0.1 0.0 3.1 3.8
Joey Graham 20 20 16.2 18.0 7.4 7.7 1.8 3.1 1.1 1.2 0.4 0.2 2.8 3.4
Raymond Felton 30 25 18.9 12.3 5.3 5.2 8.9 10.4 2.0 2.5 0.2 0.4 3.6 4.4
Danny Granger 23 12 16.0 19.6 10.5 11.2 2.5 3.6 1.6 2.8 1.7 2.4 2.2 3.2
Ike Diogu 15 18 22.5 19.2 10.6 10.1 1.3 1.9 0.7 0.5 1.4 2.4 3.6 3.7
Charlie Villanueva 29 25 21.4 15.7 10.6 11.9 1.8 2.3 1.2 1.0 1.3 2.7 2.0 3.5
Deron Williams 29 30 18.0 11.7 4.0 4.0 7.5 9.6 1.2 1.1 0.4 0.2 3.0 3.2
Sean May 17 26 22.7 20.9 13.1 15.1 2.6 3.0 2.0 1.7 1.4 1.5 4.0 3.7
So how good are those projections? First of all, you need a baseline, something to compare those projections to. Typically for a baseline, you use a naive prediction, something uncomplicated, that represents the bare minimum you would expect. Lets use league average as our baseline projection, and compare it to each of Kevin's projections using RMSE to compare accuracy.
Looks pretty even. Kevin's prjections of points scoring rates was worse than the league average baseline, but his projection for minutes per game was much better. If you do this again using per game stats, you'll see that the main difference between Kevin's projections and the baseline is his accuracy in MPG. Since MPG is much more variable than any one of the those other stats, accuracy here trumps accuracy elsewhere.
If you wanted to, you could improve the baseline by including additional information. The most relevant would probably be draft position. But then you'd end up with a projection model that probably looks a lot like the one Kevin already has. (I did something like this, and managed to outperform Kevin's projections in every other stats category except MPG. But, once again, Kevin's accuracy in that category trumps his being outperformed elsewhere.)
My purpose here wasn't really to talk about Kevin's projections, per se, but to note that talking about accuracy in projections is meaningless without some kind of baseline against which to measure. _________________ ed
The baseline comparison is a helpful addition of rigor. I thought the topic was worth a brief mention and I am glad it drew some additional comments and more depth. Sometimes hard to know what will catch interest. Some posts attempt to be comprehensive, this one was intended as a starter. My comments about the minutes being pretty accurate and the points low were brief but they end up still being main summary points I take away. We all make choices when to be brief and when to elaborate, as you choose to emphasize the baseline and preferred to go relatively brief on description of your own prediction results and method. More detail is often "worth it" but I accept your choice.
P.S. Daviswylie: I looked at a couple of your pages
I dont know if you wish to discuss or if it is done. Was this by formula by age and and a general career curve and/or did you look at comparables and make refinements for each player? Looking at the gain/loss lists below the teams I have pretty major concerns when I see C Webber as a projected major gainer and Kobe Bryant as the biggest projected loser for next year but I will wait to hear more about method / willingness to discuss it before I go further.
Joined: 13 Oct 2005 Posts: 183 Location: Atlanta, GA
Posted: Thu May 18, 2006 12:07 pm Post subject:
Thanks, Mark... After taking a CS class, I finally learned how to post pages like that up on the internet!
Regarding the Defensive PER's: sadly, they are done using the same methodology as the B-R.com individual DRtgs, which means I had to estimate from team stats everything but blocks, steals, PF's, and DReb's. However, I hope to soon put up a more accurate defensive statistic that I created using some 82games numbers. I will post a topic on it before I do so, because I want to get input on the methodology -- currently, it ranks Vince Carter and Brent Barry as among the best defensive SG's in the NBA, and I'm almost positive that cross-matching with Jason Kidd and Bruce Bowen, respectively, is at fault, but I'm not sure how to fix it. More details to come...
The projections were built with the comparables from B-R.com (using the similarity scores), plus an age adjustment that goes something like this:
They were something I just did as a lark, so I wouldn't read a lot of accuracy into them. CWebb's massive gains come because his top three Age-32 comps were Karl Malone (Age 33 PER: 28.9), Charles Barkley (23.0), and Hakeem Olajuwon (25.5). Not really sure how to correct for that... Kobe's decline I can see more easily -- he's coming off a season he will likely never repeat, and he's crashed from a huge (26+) PER season down to about 23.3 in the past as well. I'd expect him to be around 23, not the 21.6 I've got projected. Most of the gainers/losers are your basic regression to the mean cases.
Looks pretty even. Kevin's prjections of points scoring rates was worse than the league average baseline, but his projection for minutes per game was much better.
Hmm. Disheartening.
davis21wylie2121 wrote:
I would love to hear Kevin's methodology as well, as it will likely be of benefit to my "system".
I built a database of players who went straight from college to the NBA from ... I think it was like 2000-01 to 2003-04, something like that. I compared their performance during their last college year to their NBA rookie seasons, and applied that to the college crop, with an adjustment for schedule strength.
This has a little more and you can follow the links.
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