People tend to think economics is just about stocks, bonds, and money. Certainly these are topics that many economists find interesting (I don’t know these economists, but I have heard stories). The broader subject of economics, though, is about resource allocation. From the perspective of this broader view we see economists look at such topics as the economics of happiness, crime, and marriage. Of course such topics are important. But not quite as important as the impact Stephon Marbury will have on the Boston Celtics efforts to repeat as NBA champions.
The Starbury Consensus
The consensus on this move appears to be as follows:
- Marbury is a very good player. In fact, Paul Pierce said his talent is “undeniable.”
- Marbury does not help a team’s “chemistry.” In other words, his lack of talent as a teammate is also difficult to deny.
Measuring “talent” and “chemistry” is quite difficult. What we can do is think about this move in terms of resource allocation.
The primary resource players wish to consume is minutes and shots. As is often noted, rewards in basketball (i.e. salaries, awards, etc…) are driven by scoring. And players can’t score if they don’t get minutes and shot attempts.
Although scoring leads to more money and attention for players, coaches are rewarded by wins. Therefore coaches should allocate minutes and shot attempts so that the chance of victory is maximized.
Resource Allocation at the Point
With this focus in mind, let’s look at what Marbury brings to the Celtics. Starbury is a point guard, so therefore his minutes will come at the expense of Rajon Rondo and/or Eddie House. Here is how these players compare with respect to WP48 [Wins Produced per 48 minutes]:
Rajon Rondo in 2008-09: 0.356
Eddie House in 2008-09: 0.157
Stephon Marbury in 2007-08: 0.036
Stephon Marbury in 2006-07: 0.070
Stephon Marbury Career: 0.105
Average WP48 is 0.100. So Rondo amazing (in fact, he is the most productive Celtic), House is above average, and in recent years Marbury is below average. Such numbers tell us that Boston is not helped by a re-allocation of minutes towards Starbury. When we look at the individual statistics we can see why.
The individual stats tell us why Rondo is so productive. He excels with respect to shooting efficiency, rebounds, steals, and assists. House is not quite as productive, but because he’s a very efficient scorer and avoids turnovers, House is also above average.
And then there is Starbury. As I have noted in the past (see Starbury Loses His Star and The Wages of Wins is Factorial), Marbury might be “talented” but his productivity is not exceptional. For his career he is below average with respect to rebounds, steals, and turnovers (the net possession factors). He is above average with respect to taking shots, but for his career he is a slightly inefficient scorer.
In addition, when Marbury joins the Celtics he will be the oldest point guard on the roster. In other words, not only has Marbury done less than House and Rondo recently, his age – and performance in recent seasons – suggests he’s getting worse.
In sum, even if Marbury becomes a model citizen, re-allocating minutes to Marbury will not help the Celtics win more games.
The Bigger Picture
Marbury will take his minutes from Rondo and House. But he can take shot attempts from the rest of the team. And as we saw with minutes, such a re-allocation probably won’t help either.
Last year the Celtics won 66 games with 68.3 Wins Produced. Of these wins, 59.4 came from Ray Allen, Kevin Garnett, Kendrick Perkins, Paul Pierce, House, and Rondo. As Table Two notes, this year these six players are on pace to produce 66.3 wins. In sum, it is these six that are driving this team’s success.
Of course some people may not wish to focus on Wins Produced. The conventional wisdom is that scorers are good. And Marbury is definitely a scorer. But for him to score, he must take shots from someone else on the team (assuming the team’s pace is not going to change).
When we look at the Boston-Six we see that all of these players are more efficient scorers than Marbury. So even if you think scoring is all that matters in basketball, shifting shots from the most productive Celtic to Starbury is not going to help Boston win more games.
So even if Marbury is now a model citizen, the resource allocation story suggests this is not a good move. No, it doesn’t mean the Celtics can’t repeat. Starbury, though, makes this task a bit harder. And I’m afraid that conclusion – in the immortal words of Marbury — is simply factorial.
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Our research on the NBA was summarized HERE.
Wins Produced, Win Score, and PAWSmin are also discussed in the following posts:
Finally, A Guide to Evaluating Models contains useful hints on how to interpret and evaluate statistical models.