Physicists create model to try to explain the zebras of Brasileirão

When it comes to soccer, those who follow the Brazilian Championship always have some kind of guess as to who might take the title at the end of the season. Many base their predictions on the quality of the players - and hence the teams - but the favorites do not always end up in the final, and it is not uncommon for the result to be a huge zebra.

According to FAPESP Magazine, it was thinking that physicists from the Federal University of Rio Grande do Sul decided to create a computational model to try to explain the huge randomness of the running points championships, which is the format adopted by the Brasileirão. The researchers' study found that while differences in team skills are important, what really stands out is the element of surprise.

In the running point system, there are no playoffs. The 20 participating teams play a total of 38 games, facing opponents on two occasions - one at home and the other at the opponent's house. Each win yields three points, while the draw is worth only one, and nothing is gained by losing. The team with the most points at the end of the season wins the championship.

First model

At first, physicists evaluated the scores of five Brazilian and European national championships that occurred between 2006 and 2011, and based on a random phenomenon of physics - the diffusion of molecules of a solute in a solvent - created a model that generates virtual competitions with the same statistical properties as running point championships.

Thus, in this first model each molecule represented a team, and the displacement of the particles represented the teams' progress through competition through wins, draws and losses. However, this model did not work very well, and physicists soon realized that the Brasileirão score reflected another random physical phenomenon - overdiffusion - in which the probability of winning or not changing over the course of the competition.

Settings

Physicists then incorporated the fact that conditions change - layoffs, exchanges of coaches, players, injuries, and so on. -, and the model has been adjusted to take into account the teams' winning potential based on the skills of two teams playing a game. In this new model, in the event of a tie, the teams' potential remained constant, while increasing in case of victory and decreasing if defeat occurred.

This time, the simulation presented results more similar to the accumulated statistics of the last five Brazilian championships, especially because in the case of Brasileirão most teams start the competition with the same potential for victory. In addition, no team stands out from the crowd for long, due to the constant sale of players to foreign teams.

Brasileirão x European Championships

The same result was not observed in the case of the Italian and Spanish championships, in which certain teams - such as Barça and Real Madrid or Milan and Internazionale, for example - always have a higher goal average than the other teams. That's why, according to physicists, it's usually always the same teams that win the championships over there.

However, with its proper adjustments, the model broadly reproduces how team placement evolves over the course of the championship, and physicists intend to apply it to simulate the performance of specific teams and then figure out what the odds might be. that end up victorious. In addition, simulation can help explain fan questions and even solve science-related sports issues.