18 September 2015

Pred polufinale...

Ja verujem u fenomen "vruće ruke" - teoriju da igrač u košarci, ili nekom drugom sportu, može da uđe u seriju pogodaka jer je tog dana izuzetno fokusiran ili raspoložen. U bihevioralnoj ekonomiji uzima se zdravo za gotovo da među sportistima postoji "zabluda vruće ruke" (hot-hand fallacy). Kad se podaci o šutevima i ubačajima analiziraju statistički na velikom uzorku, nalaz je da je vruća ruka samo sportski mit. Mene to nije ubedilo i svoje neslaganje sam izrazio u radu objavljenom pre par godina u Kyklosu (ako je nedostupno onda radna verzija ovde), ovako:

To exemplify the rise of one, seemingly exact and scientific, thinking pattern in social science at the expense of the other less rigorous and more mundane one, let us consider the debate around the so-called “hot hand” phenomenon. Basketball players, coaches and experts traditionally believe that the player may be in a special “hot hand” condition, in which his shooting ability and performance is suddenly elevated. After a player makes several shots in a row, players, coaches and expert commentators tend to believe that his likelihood of making the next shot is higher. After examining the shooting percentages of several players in a large number of games, Gilovich, Tversky and Vallone (1985) famously showed that the “hot hand” is a myth. Shooting statistics do not in fact show any non-random increase in performance; instead, shooting percentages of players tend to revert to the mean. The study has since been universally lauded as an example of the superiority of the hard data approach to conventional wisdom and intuition. 

However, a closer inspection of the nature of the data that Gilovich, Vallone and Tversky (1985) use reveals a great degree of reductionism behind them. Shooting attempts are treated as a uniformed category, while they are in reality very diverse. Not all attempts are of equal difficulty, and there seems to be a systematic tendency towards a higher difficulty of the next shots. A player that has made one or two shots is almost always encouraged to shoot more, on his own and by his teammates and coaches. While the first few shots were made from easier positions, each following shot will tend to be attempted from more difficult positions. The opponent’s defense pays more attention to the player who has been making shots, which further increases pressure on the shooter. The shooting average of the hot hand shooter will tend to revert to the mean, not because the hot hand does not exist but because it does. The variable that adjusts is not the number of baskets but the audacity to shoot more on the side of the shooter and the intensity of defense on the side of the opponent.

Because of the complexity of the game and the loss of information that happens when basketball game shooting is placed outside its context, abstracted and reduced to data points, basketball players’ intuition and common knowledge of this matter may well be superior to the hard data. In fact, the “hot hand” experience is very compatible with the psychological concept of “flow,” later proposed by Csikszentmihalyi (1990). An expert faced with a high level of challenge may experience a state of intense and focused concentration, related to increased performance.

Professionals in many areas, including sports players, have been known to experience such states. As a former professional European and NBAbasketball player observes, in such states “the basket seems to you like a bathtub; no, like a swimming pool, and you just cannot miss it.” It is, therefore, far from obvious that the apparently sound empirical study should overrule the opinions of experienced practitioners. Even though they may well be subject to group-think and other biases, basketball professionals have the intimate, and often probably tacit knowledge of the specificities of this issue. On the other hand, once we attempt to rationally consider the issue, we tend to categorize and reduce the complex events into measurable data, thus overlooking that some potentially relevant knowledge is lost in the process.

Igrač kojeg citiram u ovom isečku je Saša Đorđević, koji je fenomen najčuvenije iskusio upravo protiv Litvanije u evropskom finalu pre 20 godina -- a publikacija iz koje sam citat izvukao je ništa drugo nego Kurir! Ne znam da li je Đorđević ranije bio citiran u međunarodnim naučnim radovima ali nešto mi govori da je Kuriru ovo sigurno bio jedini put!