Two Bocconians Develop the Capello Index

The presentation of the Capello Index at the London Stock Exchange caused quite a stir in the British press. The idea that the coach of the English national side had developed an index to measure player performance – and wanted to test it during the World Cup in South Africa – was seen as a disturbance to the team. But it's really an attempt to inject some scientific objectivity into the world of soccer, and important roles are being played by Francesco Bof, professor of sports management at SDA Bocconi, and by Sergio Venturini, who teaches quantitative methods at Università Bocconi and SDA Bocconi.
"Our work began more than a year ago", says Bof. Fabio Capello and Francesco Merighi, an entrepreneur in fantasy sports games and soccer social networking, had the idea of an index to measure objectively the performance of players on the field. The intention was to use it in fantasy football or as a support for coaches and managers considering roster changes. Bof was brought in because of the book Management del Calcio that he wrote with Fabrizio Montanari and Giacomo Silvestri in 2008.
"The first time we met, Capello already had a table of criteria that reflected his conception of how to measure soccer performance", explains Bof. "Over the months, this has become a list of over 500 possible events in a match that could affect a player's evaluation." The events involving a player during a match are worked through statistical algorithms to produce a grade similar to those published on the sports pages and useful to a professional audience. Each match updates the overall grade of a player, and the system works up dozens of statistics that show strengths, weaknesses and trends of play, over a season or a career.
Bof, who became chief index developer of the company formed to manage the index, oversees its structure and content, as well as the resources to run it. He and Venturini develop the algorithms for crunching the numbers, and their goal is to make the data available two hours after the end of a match.
It is a remarkably large project, when one considers that to analyze a match live requires two technicians and a supervisor. Then consider that after testing it on the World Cup matches, the entrepreneurs look to be fully operational for league play in England, Italy and Spain. Germany and France are also very interested.
"This system is a huge step forward in the objectivity of player evaluation", states Bof. "Compared to sports journalism ratings, the subjective element is eliminated, as is consideration of the final score. It is the team index, which is the average of the individual indices, that correlates with the result of the match." It is a perfectible system – already revised several times - that can be integrated with other evaluations.

"For example", Bof continues, "at this point we can't evaluate movement without the ball. There are some exceptions, but it is just too difficult, even if we knew all the schemes run by the coaches. But we have run thousands of tests, and the system is very robust and innovative. It doesn't rehash stats available elsewhere, and doesn't substitute other analysts. It simply gives them the tools to raise the quality of their work, and to keep improving indefinitely."