Authors: de Saá Guerra, Y., Martín González, J. M., Arjonilla López, N., Sarmiento Montesdeoca, S., Rodríguez Ruiz D., García Manso, J. M. The 3rd International Congress Complex Systems in Sports and Medicine, ICCSMS. Abstract Book. 2010. I.S.B.N.: 978-9955-15-187-6.
Research background and hypothesis. Several attempts have been made to understand some modalities of sport from the point of view of complexity. Most of these works deal with this phenomenon with regard to the mechanics of the game itself (in isolation) Nevertheless, some research has been conducted from the perspective of competition between teams. Our hypothesis was that our analysis model (Shannon entropy), for the study of competitiveness levels in the system of league competition, is a useful and high sensitivity tool to determine the degree of global competitiveness of a league. Research aim. The aim of our study was to develop a model for the competitiviness level analysis in team sport competitions, based on the uncertainty level that might exist for each confrontation. Research methods. We analyzed the degree of uncertainty or randomness of the competition, as a factor of competitiveness. It was calculated based on the Shannon entropy. Research results. We studied 17 NBA regular seasons which shows a fairly steady entropic tendency. There are seasons less competed (≤ 0.9800) than the overall average (0.9835), and periods where the competitiveness remains at higher levels (range: 0.9851 to 0.9902). Discussion and conclusions. A league is more competitive when is more random. It is harder to predict the final outcome. However, when the competition is less random, the degree of competitiveness will decrease significantly. The NBA is a very competitive league, whose teams are very balanced between them. There is a high degree of uncertainty of knowing the final result.