Barcelona among the clubs using 'Transfermarkt' for valuations of their players

The website 'Transfermarkt' is known all over the world of football. Its database contains information and statistics on over 800,000 professional footballers, including reports and stats on how much they play, transfer to other teams and a valuation on the player based on things such as age, performance and potential.

The site created by Mattias Seidel, an IT engineer and Werder Bremen fan, receives over 1 million visits every month. The site is seen as the 'unofficial' evaluator of the European football market and is used by many big clubs as a tool to value their players.

Dutch website "Follow The Money" has released a report saying that the information and statistics found on the site are just estimations made by volunteers and not 100 percent accurate.

Barcelona have even used the website to evaluate the transfers of their players. They did so when overseeing the transfer of Arthur Melo to Juventus. According to RAC 1, the club's ex-president, Josep Maria Bartomeu, referenced the site to justify the 72 million euro asking price for the midfielder.

'Follow The Money' also recounted the case in which an ex-Valencia consultant reported Jorge Mendes and Valencia owner Peter Lim for overvaluing some of the players brought in to the club. However, the case was thrown out with the valuations on 'Transfermarkt' being cited as being close to the real figures.

The website doesn't use a specific algorithm to predict player values, and the final fugure that is published is based on a decision of a larger group according to the director of international values, Christian Schwartz.

"Club's shouldn't make transfer decisions based on the figures on our website," said Schwartz.