The 2008 NBA draft has been the subject of a few posts in this forum. Two of these were penned by Erich Doerr before the draft:
2008 Win Scores NBA Draft Preview
In addition, I wrote the following soon after the draft:
Falling in Love with Potential on Draft Night (and Erich also offered the following Draft Recap at Draft Express: Win Scores 2008 NBA Draft Recap)
Each of these posts referenced Win Score, the simple metric of player performance discussed in The Wages of Wins. Today’s post is also going to employ Win Score in looking at the 2008 NBA draft.
Finding a Reference Point
The difference is that today’s post is going to introduce some important reference points. Specifically, I have calculated the average college Win Score per 40 minutes [WS40] at each position from 1995 to 2008 (the specific data set considers all players who were drafted in these fourteen seasons, and who played at least 500 minutes their last season in college).
Here are these averages:
Centers: 12.30
Power Forwards: 12.48
Small Forwards: 9.92
Shooting Guards: 8.43
Point Guards: 7.30
The numbers essentially follow what we see in the NBA. Big men – because they rebound in greater numbers and tend not to turn the ball over – post higher Win Scores. Smaller players are the opposite and post lower Win Scores. Because positions in basketball are complements in production (economic talk for the idea that teams appear to need all positions to produce wins), it makes sense to evaluate a player relative to what we generally see from a player’s position.
Back to the 2008 Draft
To put these numbers in perspective, consider the performances of Mario Chalmers and Roy Hibbert. Chalmers – a point guard – posted a 10.38 WS40 (Win Score per 40 minutes) last season. Hibbert’s WS40 was 12.89. If all you look at is Win Score – and you don’t consider position played – you might conclude that Hibbert did more in college last season. But because Hibbert is a center, his performance relative to the average at his position was not as impressive as what we saw from Chalmers. Although both were above average, Chalmers was simply the more impressive.
Table One moves beyond a simple comparison of Chalmers and Hibbert. Looking at this table – which reports what all players drafted out of college in 2008 did during the 2007-08 college season — we see a story that is quite similar to what was noted in past posts on this last draft.
Table One: Reviewing the 2008 NBA Draft with Win Score
The top players in this draft class – according to the 2007-08 college numbers – were Michael Beasley and Kevin Love. Derrick Rose – the first player taken in the draft – was actually out performed by fifteen other players taken out of college.
Now what does all this mean?
- There is a relationship between numbers in college and the NBA. And in a moment I will explain where that relationship will be discussed.
- The consistency between college and professional numbers in the NBA exceeds the level of consistency we see in professional numbers in baseball or football. In other words, basketball players are more consistent from college to the pros than baseball players are from one season of Major League Baseball to the next.
- All that being said, these numbers are not a guarantee. It’s perfectly possible for a below average performer in college to become an above average performer in the NBA. Likewise, above average college numbers do not guarantee an above average NBA performance.
So what does this tell us about players like O.J. Mayo, Eric Gordon, or Joe Alexander? Each of these players was well below average last season. And each was chosen in the lottery. Does this mean that the Grizzlies (who now have Mayo), the LA Clippers (who drafted Gordon), and the Bucks (who selected Alexander) all made a mistake?
Not necessarily. Again, it’s possible that a player who was below average in college could perform quite well in the NBA. But the odds are somewhat against this outcome. Consequently, one would think that decision-makers on these teams at some point had to consider why these players performed so badly in college. And furthermore, each team should be able to explain why each player will become transformed once each starts collecting money from the NBA.
Let me emphasize this point. The ranking of players in Table One is not necessarily what we will see in the NBA. But we can expect there will be a statistical relationship between what we see in Table One and the final outcomes we will see when these players play in the Association.
One more note on statistical relationships… I do not find a statistical relationship between relative college performance and draft position. At least, that’s the story in 2008.
And one last note on the draft…our next book has an entire chapter devoted to this subject. Hopefully that chapter will address many of the questions people have about evaluating college performance and predicting the future in the NBA (it will certainly address the link between college and NBA numbers).
Brief Comment on Non-Sports Economics
Before I close this post, as an economist I feel I have some obligation to comment ever so briefly on our recent economic troubles. Beyond sports I am very interested in economic history (as well as the history of economic thought). In light of what I know of these subjects (and what I teach), I have two quick comments:
- It would probably benefit observers – who invoke the Great Depression in talking about recent events — to actually understand the events of the Great Depression. More specifically, I think people should know that we are a long way from another Great Depression. And if you understood the details of the Great Depression you would see why comparisons between now and then are an immense stretch.
- In addition, I am quite irritated by people who discuss the proposed bailout as an example of “creeping socialism.” Such people tend to throw out the “socialism” word whenever people discuss the government playing a role in the economy. One only needs to read Adam Smith (as well as John Maynard Keynes and many, many recent economists) to see that government does indeed have a role to play in a market economy. Certainly the extent of the role is a matter of debate. So it’s possible to disagree with the need for this bailout. But you have to try harder in making your argument than just saying “creeping socialism.” My sense is that people who evoke such terms couldn’t pass a test on the actual nature of socialism (and therefore, should stop using such language).
Okay, those are my brief thoughts. As you can see, there are number of non-sports blogs linked to on the right. For more information, I strong urge people to click on over and see what the following seven blogs have to say on this subject of the current financial crisis and the proposed bail-out:
Paul Krugman-Conscience of a Liberal
– DJ
The WoW Journal Comments Policy
Our research on the NBA was summarized HERE.
The Technical Notes at wagesofwins.com provides substantially more information on the published research behind Wins Produced and Win Score
Wins Produced, Win Score, and PAWSmin are also discussed in the following posts:
Simple Models of Player Performance
What Wins Produced Says and What It Does Not Say
Introducing PAWSmin — and a Defense of Box Score Statistics
Finally, A Guide to Evaluating Models contains useful hints on how to interpret and evaluate statistical models.
Wages of Wins Journal 
Jeff
September 30, 2008
Moving to Utah is not a good way of surrounding yourself with people that use terms like socialism or government appropriately.
Italian Stallion
September 30, 2008
Personally, I think a wipeout of the global financial system would certainly assure a depression. I also think the fact that the entire financial system is in play to be incredibly obvious given all the derivative exposure.
Erich
September 30, 2008
We live in interesting economic times, for sure.
Just a few corrections to your table:
Joey Dorsey is in Houston (after draft day trade)
Donte Greene is in Sacramento (traded more than an MBS)
Sonny Weems is in Denver (these apparently are all trades)
Patrick Ewing Jr. is a Knick
Sean Singletary is a Sun (via Houston)
Devon Hardin signed in Turkey (I think, to the same team that signed Chris Lofton and another 2008 prospect)
It is probably not worth updating the table, but hopefully those concerned will find this footnote.
Vince Gagliano
September 30, 2008
If we only consider the players from Big Six conferences, then Beasley, Love, and Maarty Leunen were the three most productive players
Chris
September 30, 2008
Hey Jeff,
Thanks for adding to the conversation with that witty commentary on all things Utah. You sure have shown us how to analyze things cogently.
Jimbo
September 30, 2008
Sure looks like the Spurs got a great deal picking George Hill.
M
September 30, 2008
You could argue that the LDS church practiced economic “socialism” in the early years and is a form of “government” broadly defined. It shares some basic philosophical beliefs about the importance of community and relationship of the individual to the community with various other advocates of authority structures. There are debates about individual autonomy and collective authority and then there are debates over which collective authority should rule. State, church, or corporate. Or even intellectual.
Alex
September 30, 2008
“Moving to Utah is not a good way of surrounding yourself with people that use terms like socialism or government appropriately.”
Perhaps. But one can very easily surround yourself with people who use those terms inappropriately in NY or Chicago or LA, whereas in those cities one cannot hike the Escalante or watch the aspens turn in Zion. (October in Utah could possibly be the best month in any place in the entire country – in my opinion, at least.)
In any case, even though I understand that there is some kind of strength of schedule adjustment involved with the calculation of Win Scores for college players, I still have a hard time believing that the Win Score of a player playing at Indiana-Purdue or Rider can be appropriately compared to the Win Score of a player playing at Florida or UCLA.
MarkT
September 30, 2008
This will make for another interesting test of the WoW model, given the discrepancy vs NBA picks and the results here. I am particularly interested in OJ Mayo and Eric Gordon’s outcomes. Curious how this model seems to favor upperclassmen for some reason.
Erich
September 30, 2008
Additional economic news link for those that only understand basketball:
http://freedarko.blogspot.com/2008/09/fd-guest-lecture-dribble-down-economics.html
Daniel
September 30, 2008
According to this analysis, the Spurs made off like bandits– with all their picks. Awesome.
Bill
September 30, 2008
I am unclear on whether the WS40 is adjusted for strength of opponents. Some scouts would not be supprised by Hill being ranked the equal of Chalmers, but I have not seen any who would rank him superior. Still the Spurs did darn good with the 26th, 48th, and 58th pick.
Charles Follymacher
October 1, 2008
What Bill said. Also, two words: Walter Sharpe. I love x-factors.
Bill
October 1, 2008
” My sense is that people who evoke such terms couldn’t pass a test on the actual nature of socialism (and therefore, should stop using such language). ”
Well, since even Karl Marx could not give a coherent explaination of Socialism, it pretty much puts everyone in the same boat.
Mountain
October 1, 2008
The college game is significantly different than NBA. Mostly clearly metric credit for 3 pointers will exaggerate quality scores of most who take them in college compared to what they will do in pros. Steals probably easier in college than other stats? I’d guess that drivers will find it somewhat easier in pros with court further spread and zones not as tight. Post play tougher due to far better and on average bigger players but less double teams. Hard to say quickly how that balances out on average. Depends on player’s size and offensive style.
Josh Lewis
October 1, 2008
Dave,
I appreciate the explanation in this post of value being relative to position. I’m sure you’ve covered it somewhere along the way before but could you go into greater depth as to why you use Win Score to compare the value of players especially when it comes to end of year awards such as MVP voting.
Additionally, does the position adjustment account for 100% of the difference we see among positions, making an objective comparison possible across positions for such purposes?
I’m sorry if this is a dumb question but it seems that a lot of the criticism WoW gets on these boards is due to the misunderstanding of the relative values of each position. In essence, I believe the Kobe lovers claim that Kobe is a greater value above other wing players than say Dwight Howard is over centers. It’s easy for these folks to point to the Center position shooting a high percentage and rebounding a lot as the reason why their absolute Win Score would indicate a greater value for post players.
Any comments or clarification from you would be awesome. Thanks for all of the good work here.
dberri
October 2, 2008
John,
For MVP voting I look at Wins Produced and WP48. These metrics are adjusted for position played. As noted, we see clear differences in what players do at each position. Therefore it makes sense to measure performance relative to the average at each position.
Once you consider average performance at each position, you can make comparisons across positions. And when we make that comparison we see that Dwight Howard does more (relative to an average center) than Kobe does (relative to an average shooting guard).
Hope that helps. There were some posts early on looking at Jordan and Rodman that might provide even more discussion of this point.
Josh Lewis
October 3, 2008
Thanks DB, I’ll look up the Rodman/Jordan posts.
Does the Howard/Kobe issue also relate back to the short supply of tall people? There is less competition for outperformance at center than smaller positions making it more likely that a great Center would be “most valuable”? OR, would a normal distribution of talent imply that outperformance shouldn’t necessarily come from any position (once adjusted for position).
dberri
October 5, 2008
Josh,
The short supply of tall people indicates that there is a greater range of talent at the center and power forward positions. Consequently, it is easier for an elite talent to distance himself from the average.
You can adjust for the effect by looking at how many standard deviations a player is beyond the average.