The Significant Game

Michael Oliver's decision to award a last minute penalty to Real Madrid against Juventus was a controversial one. There were immediate protests by the Juventus players following which Gianluigi Buffon saw a red card for dissent in his last Champions League game of his career. After Cristiano Ronaldo converted the penalty for a last minute winner, the discussion then took to social media resulting in threats to Michael Oliver and his wife over the following weeks. Let's have a look at the most controversial refereeing decisions in the Champions League. As a proxy for how controversial a decision is we will use the Google search interest for the referee in the month of a Champions League fixture led by the same referee. Google Trends data starts in 2004 and I looked at referees with the most CL matches since 2009 which should cover the most influential referees. There is some manual data cleaning necessary as search interest can also be influenced by other factors, e.g. other

Possession is probably one of the football statistics which is cited most often. It has gained even more media attention as we have seen larger divergence in possession across teams. Frequently game approaches of teams are broadly categorized between possession-oriented and counter-attacking: think about Barcelona, Bayern Munich, Manchester City vs Chelsea, Borussia Dortmund and Liverpool. At first glance the possession statistic seems to be fairly trivial; who controls most of the ball during the 90 minutes? There are however some details that can have quite an impact on the final number. The simplest approach is to approximate possession with touches. This can however favour teams that try to play short and controlled passes and prefer a slow build-up play. On the other extreme you could try to assess possession for every second of the game, even interpret a uncontrolled clearance as giving up possession. The OptaPro Blog has written a very good article on this exact topic. In thi