New Study Identifies NBA Players Who Shoot Too Much

To reach the NBA Finals, Russell Westbrook of the Oklahoma City Thunder needs to pass more, especially to his teammate Kevin Durant.  That would be the message that two researchers would send to Thunder coach, Scott Brooks, if given the chance.  Matt Goldman, a graduate student at the University of California, San Diego, and Justin Rao, a research scientist at Yahoo Labs recently named Westbrook as the biggest “chucker” in the NBA because of statistics showing that he shoots much more often than he should, while Durant is classified as an undershooter, whose team would benefit from him taking more chances.

While their statistical theory builds a case for how to achieve optimal efficiency on the court, they don’t explain why elite players make the in-game decisions that they do.  For that matter, what about the high school ball player or the weekend warrior at the gym; how do they make the decision to pass or shoot?  For that, Markus Raab and Joseph Johnson, both sport scientists, have some insights  from their research.

First, let’s do the numbers.  Goldman and Rao dug into the NBA stats archive to analyze over 400,000 team possessions over the last four seasons, 2006-2010, across the entire league.  In a paper and presentation at the recent MIT Sloan Sports Analytics Conference, they presented a model that compares the difficulty of a shot taken in relation to the time remaining on the 24 second shot clock.  Then they compare this with a concept called “allocative efficiency”, or the benefit of equally distributing the ball to any of the five players on the court and also “dynamic efficiency”, or deciding whether to “use” the possession by taking a shot or “continuing” the possession by making a pass.  As the shot clock winds down, the marginal difficulty of a shot considered will need to rise or they risk getting no shot off before the 24 seconds expires, wasting the possession.

They found that most NBA  players are very efficient in their shot selection.  Surprisingly, several elite players are actually not shooting enough, according to their model.  Here is the list of all NBA players analyzed and their score, where a negative number (at the top of the list) represent overshooters.  Joining Westbrook at the top of the list were well-known names like Lamar Odom and Tracy McGrady.  Even bigger names like LeBron James, Ray Allen, Dirk Nowitzki, Chris Paul and Joe Johnson actually show up at the bottom of the list and may hurt their team with their unselfishness.

So, what goes on in these very well-paid athletic brains?  Are the trigger-happy players selfish, over-confident and in need of attention?  Markus Raab, professor at the German Sport University-Cologne, and Joseph Johnson, professor at Miami University of Ohio,  have spent the last ten years studying the decision-making processes of athletes in several different sports, but especially fast-paced games where quick decisions are critical.

Let’s imagine the Thunder point guard, Westbrook, bringing the ball up the floor.  He crosses the half court line and his decision making process kicks in.  The Raab/Johnson process first recognizes that perception of the situation is required before the player can generate all of the different options in his brain.  Just like a quarterback examining and identifying the defensive alignment as he breaks the huddle, the point guard in basketball has to visually process the scene in front of him.  From there, his brain, based on his vast memory of similar basketball experiences, begins to make a list of options.  These can be spatial options, like move the ball left, ahead or right, or functional options like pass or shoot.  

Through research with basketball and team handball players, the researchers found that the most effective strategy is to “take the first” option that the player conceives as that is most often the “correct” choice when analyzed later by experts.  Much like going with your first answer on a test, the more that you deliberate over other choices, the greater the chances that you’ll pick the wrong one.  

However, each player will have their own library of choices stored in their memory and this magical sorting of best options can be influenced by several unique variables.  

One of these pre-determined factors is a personality preference known as action vs. state orientation.  According to Raab, “An action orientation is attributed to players if they concentrate on a specific goal and take risks, whereas a state orientation is attributed to players if they have non-task-relevant cognitions and reduce risk-taking behavior by considering more situative considerations and future behavioral consequences.”  In other words, someone who has an action mentality is more likely to shoot first and ask questions later, while a state oriented player is going to consider more options with more long-term outlook.

For this and similar experiments, Raab and Johnson showed first-person videos of many different basketball in-game scenarios to players of different skill levels and personality types, then froze the scene and asked them to make a quick decision of what to do next with the ball.  They recorded the decision and the time it took to make the decision.  They found that those players who have more of an action orientation, according to a personality test given prior to the drill, were more likely to shoot first and more quickly.  Clearly, Russell Westbrook must fall in this category.

Raab followed up this study with a similar one that measured the difference between intuition-based decisions and more cognitive, deliberate decisions.  A player who “goes with his gut” was shown to make faster and more successful choices than one that over analyzes.  This may help explain the list of elite players who tend to pass more than shoot.  They have more experience and patience to rely on their intuitive feel for the game.  While Goldman and Rao may ask them to be more action oriented, these players have learned that they are often just one more pass away from a much higher percentage shot.

Certainly, this is the tip of the iceberg regarding the psyche of a player at any level.  There are many more variables, some fact-based (I’ve missed my last 5 shots, so I’m going to pass) while some are more emotional, (I don’t want my teammate to get all the glory.)  For now, Thunder fans can only hope that their point guard learns to share.

See also: Are Bank Shots Best In Basketball? and NBA Teams Win With Ethnic Diversity

NBA Teams Win With Ethnic Diversity

When the National Basketball Association Conference Finals tip off later this week, four teams will test their level of cooperation, unselfishness and teamwork. One issue that apparently will not get in their way is diversity.

Two new studies have shown that an NBA team's level of racial or ethnic diversity does not have any significant impact on its winning percentage or its players' split-second decision making on the court. These reassuring findings on player unity contrast with a 2007 report showing same-race bias among NBA referees when making foul calls.

The demographics of the NBA have changed dramatically over the last 40 years. African-Americans make up about 76 percent of the league's players, while Latinos and Asians account for three and one percent, respectively. According to the NBA, 77 international players from 32 countries contributed just over 17 percent to team rosters. There are not only potential ethnic and cultural barriers, but also language differences that may impact a team's chemistry.

For any organization, results matter. However, few groups of co-workers have their teamwork watched, measured and analyzed to the extent of an NBA team.

Diversity measured 
Paul Sommers and Jessica Weiss of Middlebury College wanted to see if the level of an NBA team's diversity affected its ability to win. For the last three complete NBA seasons (through 2007-08), players who had at least 800 minutes of court time were divided into one of five racial or demographic groups; African-Americans, Caucasians, East Europeans, Asians, and other foreign-born players who did not play either high school or college basketball in the United States. Using the Herfindahl-Hirschman index (HHI) to measure diversity, a number was assigned to each team for each season. An index of 1.0 would indicate a completely homogeneous team, while more diverse teams would score lower (between 0 and 1).

When the HHI was regressed against each team's regular season winning percentage, no significant correlation was found. In other words, a team's diversity did not help or hurt their success on the court. As supporting evidence, the last three NBA champions, the Boston Celtics (2007-08), the San Antonio Spurs (2006-07), and the Miami Heat (2005-06), had dramatically different HHIs of 1.0, .360, and .781, respectively.

What about that language barrier? If communications suffered, then there should be passing mixups and team turnovers should rise. To find out, Sommers and Weiss divided the teams into two groups, more diverse and less diverse at the median HHI for the league. Over the three seasons, there was no significant difference in total turnovers between the two groups.

The findings were detailed in last month's Atlantic Economic Journal.

Carrying that on-court cooperation theme even further, Brigham Young researchers searched for same-race bias in NBA players when passing to their teammates. To put it bluntly, would a white player subconsciously prefer to pass to another white player if given a choice and, conversely, a black player to a black player? In an exhaustive study, Joseph Price, Lars John Lefgren and Henry Tappen dug into six seasons of NBA data to look at every assisted basket and recorded the race (noted simply as "black" or "not black") of the passer and the scorer. They also noted the other three players on the floor when the basket was made. Of course, there were numerous decision variables that the researchers had to eliminate to isolate just racial preference.

The conclusion: No same-race bias was found in the passing patterns of NBA players.  Study details are available from the Social Science Research Network as part of their working paper series.

Referees don't play fair
Joseph Price is known for his controversial paper in 2007 that concluded there is significant same-race bias shown by NBA referees. In that study, more than 600,000 officiating calls over 13 seasons were analyzed to see if white referees would call fewer fouls on white players than black players and vice versa (black referees whistling black players).

They concluded that the difference was "large enough that the probability of a team winning is noticeably affected by the racial composition of the refereeing crew assigned to the game.”

In fact, their data showed that players earned up to 4 percent fewer fouls and scored up to 2.5 percent more points on nights in which their race matches that of the refereeing crew. From a team perspective, the bias factor may change the outcome of two games out of an 82 game season. For some teams, that may be the difference that keeps them out of the playoffs.

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