Win Score and the NBA Draft

Posted on June 26, 2007 by


The following is a guest post from WoW Journal reader Erich Doerr. Erich has used the Win Score metric to investigate the top prospects for the 2007 NBA Draft.

In The Wages of Wins, David Berri and company introduce a basketball valuation system called Win Score. This easily calculated metric merely requires a box score and some basic math. To learn more about Win Score, check out The Wages of Wins book or numerous posts in this forum.

The Win Score model was built off of NBA statistics, but the same metric can be used to assess players entering the NBA. In past years, I found that Win Score has been particularly adept in identifying late 1st round and second round gems such as Josh Howard and Carlos Boozer. For 2006, Win Score successfully foretold slot over-performers like Brandon Roy, Rajan Rondo, and Paul Millsap while identifying underperformers in J.J. Redick, Adam Morrison, and Randy Foye.

The 2007 College Prospects, an Overview

For 2007, Win Score offers several opinions. Like everybody else, it shares excitement for Oden and Durant. More interestingly, Win Score offers opinions on who will outperform or under-perform their draft projection. Here is an over-view of these projections.

Pick Booms: Nick Fazekas, Stephane Lasme, Rashad Jones-Jennings

Views favorably: Greg Oden, Kevin Durant, Al Horford, Joakim Noah, Julian Wright, Morris Almond, Aaron Gray

Views unfavorably: Jeff Green, Taureen Green, Gabe Pruitt, Nick Young, Thaddeus Young, Wilson Chandler, Javaris Crittenton

Pick Busts: Corey Brewer, Acie Law, Spencer Hawes

PAWS and the Tier System

Let’s go a bit further into the numbers.

Chad Ford of ESPN gave an analysis of the NBA Draft based on the concept of a Tier System. In essence, rather than rank the prospects in order, Ford argues that a better system is to group players into tiers. The top tier in this draft consists of Greg Oden and Kevin Durant. Tier two includes players like Al Horford and Mike Conley.

Ford offered six tiers, consisting of both international and college players. Let’s focus on the 30 college players Ford considered and rank these players in terms of Position Adjusted Win Score (PAWS) – ranked per 40 minutes from the players last year in college.

Table One: PAWS40 and the Top Prospects

The top player according to this view is Nick Fazekas. Is he better than Oden or Durant? Not sure anyone would make that argument. Still, it does suggest he might be better than a 6th tier prospect.

The top players in PAWS40 — among the players generally thought of as lottery choices — include Oden, Durant, Horford, and Noah.

And looking at the bottom of the list…. perhaps teams should think a bit more about drafting Hawes or Aaron Afflalo.

Adjusting for Level of Competition

Since Win Score was derived from the evaluation of the NBA, there wasn’t a strong need to adjust for level of competition. The NBA teams sport a much narrower talent gap than the NCAA conferences and International leagues. In looking at college players, though, we have to note that the wider NCAA talent distribution allows for players to pick on the less skilled teams. The following tables offer an assessment of how well various players played against NCAA tournament teams, versus their performance otherwise. These tables suggest, in a very limited sample, that maybe Fazekas is not quite as good as his overall numbers indicate.

Table Two: Prospect’s per-minute Performance Against Tournament Teams

Table Three: Prospect’s per-40 minute Performance Against Tournament Teams

Looking at International Players

International leagues suffer from this problem and more. The shorter seasons provide for smaller sample sizes. Key statistics for Win Score are often not included in international box scores. To assess the 2007 class, turnover and fouling stats were approximated by taking the median rate of their draft class position peers. In spite of these issues, Win Score suggests the following:

Favorites: Jianlian Yi, Marco Belinelli, Luka Bogdanovic, Jonas Maciulis, Kyrylo Fesenko, and Mirza Begic

Buyer Beware: Tiago Splitter, Petteri Koponen, Marc Gasol, Sidiki Sidibe, and Dimitri Sokolov

Win Score loves Yi Jianlian, even if we change our assumption and have him post double the median foul and turnover rate.

More information at DraftExpress

Perhaps you wish to see more than is provided in this post. To quickly examine the scores of previous years, access the excellent stats database, select Stat Type: Usage stats and sort by WS/40 (Win Score per 40 minutes).

One can also go to the following position-by-position analysis offered by Mike Schmidt at DraftExpress, which details all the numbers for many of the top prospects in 2007.

Just by the numbers (Part One)…Evaluating this Year’s Point Guard Crop

Just by the numbers (Part Two)…Evaluating this Year’s Shooting Guard Crop

Just by the numbers (Part Three)…Evaluating this Year’s Small Forward Crop

Just by the numbers (Part Four)…Evaluating this Year’s Power Forward Crop

Just by the numbers (Part Five)…Evaluating this Year’s Center Crop

A Disclaimer and a Claim

As noted, the Win Score metric was created to analyze the NBA. Berri tells us that further research is ongoing, including studies on the college to NBA transition and player development.

While Win Score should not be used as the only basis to order up a draft board, it serves as an objective tool in assessing player performance. To my knowledge there is no better tool to identify potential difference makers after the lottery picks have come and gone.

– Erich Doerr

Editors Note: I want to thank Erich for conducting the analysis of the 2007 draft and writing up this post. Additionally, I want to note that I have read a number of very good comments posted in the last few days. Now if I could get someone to respond to those for me, then this blog could just about run itself. Seriously, thanks to everyone for the comments. I am reading these. Just can’t find the time to respond as much I like.

– DJ

Update: This article has also been posted at DraftExpress.  At DraftExpress Erich has also added even more analysis of international players.