Wednesday, February 8, 2012

Who is the best player? Which is the best Team?



In recent years, tools from network analysis have been applied to sports. For example, Duch, Waitzman, and Amaral (2010) developed a network approach to quantify the performance of individual players in soccer. Heuer et al. (2010) introduced a general model-free approach to elucidate the outcome of a soccer match. Network analysis tools have been applied to football (Girvan and Newman (2002); baseball (Petersen et al.) and basketball (Ben-Naim et al.(2007a));

In many sports, rankings are produced according to the number of victories that one team or individual has against others. But any sportsperson or fan will tell you that some victories are more important than others. For example, beating the top ranked team or individual is much more significant than beating the bottom ranked one. So a way of taking this into account in rankings would be a significant step forward. Here, I shall discuss the study done in Tennis and Cricket

Best Tennis player Ever: Jimmy Connors. Really?

Male tennis players who played in at least one Association of Tennis Professionals match between 1968 and 2010 were evaluated through network analysis. The data was pulled from the Association of Tennis Professionals website. Matches are considered as basic contacts between the actors in the network and weighted connections are drawn on the basis of the number of matches between the same two opponents. Filippo Radicchi, author of the study developed a ranking algorithm similar to PageRank and quantified the importance of players and ranked them by a “tennis prestige” score. This score is determined by a player’s competitiveness, the quality of his performance and number of victories. In this particular ranking system, it’s more important to win a single match against a very good player than many matches against not-so-good players.

Here are his results, with Jimmy Connors out front, followed by Lendl and McEnroe. Federer is back in 7th spot, behind players like Edberg and Agassi; Rafael Nadal is further back in 24th place



One of the reasons Jimmy Connors ranks on top is because he played for more than 20 years and had the opportunity to win a lot of matches against other very good players.The paper closes with another chart which restricts comparison to within individual years, thus avoiding the Gerulaitis/Nadal problem of brief careers in modern era versus long careers in earlier eras. This chart makes more sense, in that the rankings, while not always matching official ones, are plausible within the year in question

Source: (2011) Radicchi F. Who is the best player ever? A complex network analysis of the history of professional tennis. Available at: http://arxiv.org/abs/1101.4028

Best in Cricket: Australia. Any Doubts?

Top15 Captains in Test Cricket
Mukherjee, author of this study has taken Test matches played between 1877 and 2010 and One Day International (ODI) matches played between 1971 and 2010. The data is pulled from espncricinfo site. A single match is represented by a link between two opponents. Thus if team i wins against team j, a directed link is drawn from j to i. A weighted representation of the directed network is obtained by assigning a weight w(j,i) to the link, where w(j,i) is equal to the fraction of times team j wins against team i. He quantified the relevance of matches with the use of a complex network approach equivalent to the one used for the computation of the PageRank score similar to the one used by Radicchi above. He's also used it to determine the best captains overall and on a decade-by-decade basis.

Top10 Teams in Test Cricket
The best team in both test and one-day cricket turns out to be Australia. And the best captains in test and one-day cricket are Australian too: Steve Waugh and Ricky Pointing respectively, That's no surprise, given Australia's dominance of the game. More surprising is the second-placed team, South Africa, because it was excluded from international cricket for many years. Next positions were followed by England, West Indies, Pakistan, India, Sri Lanka, New Zealand, Zimbabwe and Bangladesh. South Africa’s Graeme Smith emerges as the second best captain with Ricky Ponting occupying the third position. India’s M. S. Dhoni and Sourav Ganguly finds a place in the top 20 list with 9th and 15th (Dada fans, don’t argue more!) positions respectively. Similar is the situation with ODI history where full rankings are in the paper cited below.

Source: (2012) S Mukherjee : Identifying The Greatest Team And Captain − A Complex Network Approach To Cricket Matches. Available at: arxiv.org/abs/1201.1318

Well, exploring sports like Hockey, Badminton may end up as decent papers, huh? 

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