Espn Insider Article: Introducing WPA to the masses (please post) [Archive]

024

07-30-2010, 04:33 PM

"Someone created the box score and he should be shot." -- Houston Rockets general manager Daryl Morey

The state of basketball analytics remains far behind baseball's sabermetrics world, which caught fire a little under a decade ago. While Brad Pitt, Philip Seymour Hoffman and Jonah Hill get ready for their roles in the oft-delayed "Moneyball" movie, basketball analytics remain in the infant stages, attempting to outgrow the restrictive confines of the box score.

After LeBron James, Dwyane Wade and Chris Bosh teamed up in South Beach, we stand before one of the greatest basketball experiments ever assembled on the court. Unfortunately, the archaic box score framework will do little to illuminate the unique dynamics on the court. We can't grade the Miami trio's success based on who tallies the most points or who launches the most shots. Furthermore, Wade could easily have the team's highest scoring average next season but that achievement would hardly mean he contributed the most to winning games.

The Heat will provide the ultimate test of ego management: Will James and Wade turn down a good shot for a better shot for their teammates? More to the point, will James and Wade sacrifice individual glory (scoring the most points) for the Heat's success?

Win Probability Added would hold the answer.

What is WPA? Starting with the beginning of a play, what is the probability of winning the game, given the situation? After the conclusion of that play, recalculate and debit/credit the player for the change in win probability. That's WPA. This is the essence of sport: each play contributes to a team's chances of reaching its collective goal of beating the other team.

But here's the thing: WPA hasn't arrived in basketball. Sabermetrics expert Tom Tango created this ingenious metric for baseball and Brian Burke of Advanced NFL Stats fame has recently engineered it for the football masses. But the basketball world still lacks it.

And we need it now more than ever.

Imagine the following scenario. James brings up the ball into a halfcourt set. After coach Erik Spoelstra signals for the pick-and-roll, Bosh obediently jogs to the top of the key to set a high ball screen for James. James uses the hard pick to dribble away to the right wing, luring Mike Miller's defender from the right corner, sending Bosh rolling to the basket and leaving Wade to fill the top of the key.

Hit the pause button.

In this instant, James has four options to alter his team's chances of scoring:

1) Pass to Miller for the open 3. (Miller shot 41-for-67 on open catch-and-shoots last season, according to Synergy Sports Technology)
2) Hit Bosh for a layup. (Bosh scored in 73.3 percent of such situations)
3) Hand the ball off to Wade to restart the offense. (Wade ranks as one of the top isolation scorers in the game)
4) Take a pull-up jumper off the dribble. (James hit 37.4 percent of jumpers off screens)

This pivotal moment captures the beauty of basketball. It would take even the sharpest analyst several minutes to collect all the available data at hand, design a decision tree, calculate the probabilities and finally arrive at a well-informed choice. But James has only a precious millisecond to make his move. And for most of James' career in Cleveland, the optimal choice for the Cavaliers often aligned with the optimal choice of his own -- take the shot.

But as we all know, he's not in Cleveland anymore and it may not be a good idea to choose what's behind door No. 4. It may be a better play to draw the defense and use his vision and passing skills to get the better shot. But that means fewer points for James, and less recognition in the box score.

James' mind will be forced to adjust to a new set of variables in Miami. And they're much, much better. In other words, the scoring probabilities of his teammates have risen to heights he's never seen.

This is why some believe James will become the first person in nearly a half-century to average a triple-double. He just received a new batch of toys and he can pass to them without lowering the chances his team will score. But the big question remains: Is LeBron willing to trade personal glory for the sake of victory?

It all comes down to the framework of WPA. James would have to pass up the shot that he loved to take in Cleveland because probabilistically it may be the better play with his new Super Friends. But as any coach will attest, player ego often gets in the way of a team's goals. If James swallows his pride and makes the pass to an open Wade for a game-winning shot, it won't signal that Wade is The Man, even if that's what the media would decide. In reality, it means James has fully recognized his role as the facilitator of victory, whether that's taking the big shots or creating better ones for his teammates.

Unlike the start-and-stop style of baseball and football, basketball is largely a fluid game with little opportunity to press the pause button and establish new discrete games states like an at-bat in baseball or a down in football. And for that reason, we're a long ways from developing a WPA for the hardwood.

But in the meantime, the blueprint still provides an innovative way to think outside the box score.