In this week’s Synapse, we made a game-time decision, (pun intended), to focus on the high-speed decision making skills of athletes that are critical in so many sports. There are several new research studies out that all take a different angle. However, it was an interesting post by Ross Tucker at the always excellent blog, The Science of Sport that sparked our curiosity. As a consultant to the South African rugby team, he commented on the recent World Cup final that saw New Zealand triumph over France. However, it wasn’t the decision making of the players that Tucker wrote about, but rather of the referee.
For those unfamiliar with rugby, like me, the referee must make many crucial judgement decisions during a game regarding fouls by players. As Tucker describes, “Rugby presents a unique challenge in that the referee is required to make a specific decision about a contested tackle almost 200 times a match (once every 30 seconds), and this decision is multidimensional, instantaneous and open to interpretation.” He adds, “This situation exists because so much of the contest in rugby revolves around competing for the ball after a tackle, in the breakdown contest.”
Of course, fans will always have a bias towards their team, but what if the referee has conscious or sub-conscious influences on his decisions? Tucker argues that the only way to reveal these hidden biases is to study the entire collection of calls in a post-game analysis. First, which decisions were clearly wrong and which were close interpretive calls? Of the 50-50 calls, is there a significant tendency? Is a certain team being favored or punished more? Does the home team get more favorable treatment? If there is a finding and a bias is detected, these can be part of an official’s performance review.
Consider the Options
Just as a referee has hundreds of decisions per game, so to does an NBA point guard. Every trip up the floor is full of options, especially whether to pass the ball or attempt a shot. Matt Goldman, a graduate student at the University of California, San Diego, and Justin Rao, a research scientist at Yahoo Labs recently dug into the NBA stats archive to analyze over 400,000 team possessions over the last four NBA seasons, 2006-2010, to find out who were the most efficient decision makers.
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 compared 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) represents overshooters.
Markus Raab, professor at the German Sport University-Cologne and Sylvain Laborde, researcher at the University of Caen Basse–Normandy tried to explain this decision process with a study 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.
Better Decisions for Better Agility
Deciding to take an action, like making a call or a pass, is a proactive process based on the stimuli in front of us. But, what about having to react to the actions of others? Defenders know all about changing directions in response to an attacker’s decisions. Traditionally, the ability to “read” an attacker was thought to rely on the skill of perception while the ability to change directions quickly was dependent on an athlete’s level of agility. However, researchers in the School of Human Movement and Sport Sciences at the University of Ballarat and the Canberra Raiders Rugby League Club, both in Australia, were curious if better perception could improve a player’s agility.
They first had to accept a new definition of agility. Rather than being a “closed motor skill” without influence from outside stimuli, agility is now being thought of as an “open skill” that should be measured as the ability to change directions in response to an unpredictable actor, either the ball or an opposing player. So, the ability to perceive and react quicker should help the speed which an athlete can move in a new direction.
Lead researcher Benjamin Serpell and his team recruited fifteen under-20 rugby players and split them into two groups, one which would receive reactive agility training and one which would serve as control group. After taking baseline reaction agility tests (RAT) and change of direction speed (CODS) tests for all players to test their levels of agility, the experimental group trained for three weeks by watching videos of elite rugby players just before they either passed the ball or changed direction.
The young players were instructed to watch the shoulders, trunk and hips of the elite players as a way to anticipate their next movement. Both groups were brought back together and retested. The trained group showed significant improvement in the agility tests while the control group was held constant. Serpell concluded that perception and decision making are linked with overall agility and that coaches should try to design training sessions that include both.