As we have noted over the past couple of weeks, today (May12th 2012) Barnes&Noble will be offering Stumbling on Wins as the Deal of the Day at an absolute steal for $1.99!

The book addresses many questions, including…

• Was Isiah Thomas a victim of his player budget?
• Do hockey goalies matter?
• Why should basketball players go pro after appearing in the Final Four?
• Do coaches have any impact on an NBA player’s performance?

Also, if you’d like to help spread the word please pass this along.

A little over a year ago, NBA “experts” were telling us that the Knicks are now much better – and the Nuggets are now in trouble — because Carmelo Anthony was playing in New York. The Knicks clearly concurred when they gave Melo a maximum player salary.

Now we are hearing how the Warriors must be tanking – and the Bucks are improved – because Monta Ellis departed Oakland for Milwaukee.

In both instances, the team that got the “star” was supposed to be much better. And the team losing the “star” was doomed.

It is these storylines that led me to write the following for Huffington Post.

Should You Be an NBA Star for Taking Shots or Making Shots?

This article makes the following simple observations (and I hope everyone sees the simplicity of these observations):

• Scoring totals are driven by shot attempts and shooting efficiency (that should be obvious).
• Shot attempts are not really “created” but are generally just “taken” from a player’s teammates (may not be obvious, but I think this is clear when you look at the data).
• Therefore, in evaluating a player’s scoring prowess, scoring totals can be deceptive and we are better off focusing on shooting efficiency.

In other words, the NBA shouldn’t reward players for taking shots (from their teammates).  The NBA should reward players for making shots.  Yes, basketball should be this simple!

In the case of Melo and Monta, each player has not been consistently good at actually making shots.  And that should mean that people shouldn’t be arguing that either player is really a “star”.

Or, to put it yet another way, I suspect that if both Melo and Monta took fewer shots – and didn’t average more than 20 points per game – no one would think they are “stars”.

And that is the simple message I would like to convey to basketball fans and “experts”.  You shouldn’t be fooled by scoring totals.  If a player is just taking shots from his teammates – and not making a high percentage of these shots – then he is not helping (with respect to this aspect of the game).

Let me close this brief post with one more observation:  It seems to me that I have read a number of stories recently about how Melo is not a “star”. These stories seemed motivated by the Knicks inability to win with Anthony.  Here are my questions…

• …where were these people a year ago?
• …and is anyone learning from this experience (like they “learned” from the Iverson experiences)?

- DJ

Readers of Henry Abbott’s TrueHoop blog might have seen the following today:

Writing about the deal to keep the Kings in Sacramento, at great expense to the city, Dave Berri notes on the Freakonomics blog that 85 percent of economists agree that state and local governments should not subsidize professional sports. Then he explains that “professional sports in North America have evolved into a very odd industry. Typically we tend to think that firms need capital and labor to produce goods; and owners of the firm are responsible for providing the capital. But in sports, much of the capital is provided by the state (see the Baade and Matheson study for how much the public subsidizes professional sports arenas and stadiums). Given this trend, what are the owners providing? In other words, why does Sacramento need the Maloofs (the “owners” of the Kings)? It certainly doesn’t appear to be for managerial expertise.”

My comment at Freakonomics focused on how the NBA is able to get people who do not like basketball to contribute to the sport.  There have been a number of comments at Freakonomics, but I thought I would highlight three observations Andres Alvarez passed along this afternoon.

1. If the city was going to invest in a business to “help the economy” why would they invest in a bad one? It seems odd to ask taxpayers to pay for a business that has been doing terribly and shows no signs of changing.

2. A commenter at Freakonomics made the point people are irrational about sports. He even posited if they split the cost and asked taxpayers to each pay up $250 to save the team, he would gladly pay. Why not do this? If this for the fans and uses public money, why not just say “How many of you are willing to pay an extra X hundred a year for this team?” 

3. Final note: NBA has incentive laden contracts. Why not just build that in? We’ll finance the stadium and IF we see an X growth as your economists projected then good. If not then it’s a loan we expect interest on.

I would add… this entire story illustrates how the NBA uses its monopoly power to extract money from cities.  And this is similar to how the NBA uses its monopsony power to extract money from its players.  Yes, power does matter in negotiations.

- DJ

Wayne Winston has a short post on John Hollinger’s Player Efficiency Rating.

Hollinger’s PER Ratings Demystified

Here is Wayne’s entire post (in case you didn’t feel like clicking over):

I have had a great time teaching a sports and math class to Kelley School of Business students at Indiana University. One of my ace students Paul Aynilian did a study trying to estimate John Hollinger’s famous ESPN PER Ratings based on box score statistics. We found that

45.75*(Points/Minute)+22.55*(Rebounds/Minute)+32.8*(Assists/Minute)+58.2*(Steals/Minute)-48.65*(Turnovers/Minute) -39.73*(Missed FG’s per minute) -20.6*(Missed FT per minute)+38.37*(Blocked Shots Per Miute)-18.68*(Personal Fouls Per Minute)

explains over 99% of the variation in this season’s PER rankings  and is off by an average of .37 in estimating the PER of the top 200 NBA players whose stats are on Yahoo.com. So basically our simple formula virtually duplicates the PER rating without a lot of mumbo jumbo.

The disturbing thing about these weights is that if an NBA player shot 33 .33% (1-3) then the more shots they take the higher their PER because shooting 1 for 3 gives you a net contribution of 2(45.75)-2(39.73)>0!! Clearly this is bad because a 33% shooter is not a good shooter and with these weights the more shots a bad shooter takes, the higher his PER rating.

Let me add a bit to this story.  We can also see how well PER explains wins with a simple regression of team wins on a team’s PER. The results indicate that PER only explains 33% of team wins. You can do better if you add the team defensive measures used in Wins Produced. Those factors increase explanatory power to 55% (if you weigh the team defensive factors as they are in Wins Produced) or 82% (if you allow the weights of each individual factor to vary). Either way, PER does not explain 95% of team wins (as we see with Wins Produced).

In sum, PER is a model that is not theoretically sound (yes, it over-values inefficient scoring) or empirically sound (it doesn’t explain wins). So why is it so popular? I am going to offer four explanations:

1. PER certainly looks like a very complicated formula. And so it is easy for people who are not mathematically inclined to think it is “advanced” (although it is highly correlated with the much simpler NBA Efficiency metric – which few people think is “advanced”).

2. Measures like PER and NBA Efficiency are not about “efficiency”. But they do explain – as noted in Stumbling on Wins — player evaluations. In other words, these “advanced” measures are consistent with popular perceptions.

3. Hollinger writes at ESPN, which is a very large platform. Clearly this gives his work wide exposure. And this exposure has led writers who are not at ESPN to quote PER often.

4. And finally, Hollinger doesn’t respond much to criticism. Back in 2006 he responded to something I said once. But that was it.

Hollinger simply doesn’t spend much time addressing the problems with his model. And I think that might be an effective strategy. Addressing your critics is something we encourage in academia. At least, at our academic meetings, discussants are assigned to each paper and these discussants are supposed to critique your work. This process is supposed to make the work better. But outsider of academia, I am not convinced that addressing critics has the effect that academics suspect.

Paul Krugman, for example, frequently addresses his critics. But he clearly is not well-loved by these same critics. The problem is that although Krugman addresses his critics, he clearly doesn’t agree with these people. And that is the problem for these critics.  People don’t want their criticisms addressed. They want people to agree with these criticisms. When that doesn’t happen, well…these critics get very angry.

So I think Hollinger has probably taken the correct path. By essentially ignoring his critics he has defused a great deal of hostility. And that might have had a small impact on the popularity of PER.

However we explain the popularity, it is clear that – no matter how often Wayne and I point to its flaws — PER is not going away. As long as Hollinger and the other people at ESPN (and other people in the sports media) want to use this measure to evaluate basketball players, this measure — with all its flaws — will remain part of the discussion of player value in the NBA.

- DJ