Chelsea, Manchester United, and Martin Atkinson - Anatomy of a Refereeing Controversy

There's been understandably a lot of noise from Manchester United fans about how Martin Atkinson's decisions impacted their recent match with Chelsea for the worse. I'm inclined to sympathise here - David Luiz should almost certainly have been sent off on multiple occasions, and the penalty Chris Smalling conceded did indeed look fairly soft. It's pretty futile to speculate on how matches turn out if you change just one thing about them, but I decided to give it my best shot to see just how Atkinson's questionable decisions impacted the game.

So, I took the specific calls that I remembered as questionable and decided to hit up win probability to determine just how valuable each call was to each team. Please note that all I'm doing here is flagging potential problems rather than passing judgment (yet). Anyway, let's take a look after the jump.

• 2 min: Fernando Torres disallowed goal. Florent Malouda takes a corner kick, David Luiz and John O'Shea tussle in the box. As the ball is nodded out, Atkinson blows the whistle for an alleged foul; Torres volleys in off the crossbar. Replays show that the case for a foul is a weak one at best, and that the goal should have stood. Chelsea: -0.68 pts. Manchester United: +0.59 pts.
• 4 min: Michael Carrick not booked for yellow card offence. Martin Atkinson plays advantage as Chelsea break down the right, but Carrick's sliding takle on Ramires is very late and probably should have seen him receive a booking. Chelsea: -0.05 pts. Manchester United: +0.05 pts.
• 5 min: John Terry handball ignored. Nani shoots from range, shot is blocked by John Terry, whose arm does quite a lot of the blocking. Arm is not raised for an obvious handball, but replays clearly shot that it is technically a handball in the penalty area. Chelsea: +0.59 pts. Manchester United: -0.60 pts.
• 40 min: Nemanja Vidic handball ignored. Frank Lampard free kick saved by Edwin van der Sar, followup shot by Branislav Ivanovic also saved by van der Sar. Ball is deflected onto Nemanja Vidic's arm. Unintentional but technically a handball in the box, though slightly weaker claim than the Terry handball earlier in the match. Chelsea: -0.67 pts. Manchester United: +0.75 pts.
• 58 min: David Luiz not booked for challenge on Javier Hernandez. David Luiz catches Javier Hernandez with arm in off ball offence. Not seen by Atkinson, yellow card deserved but not issued. Chelsea: +0.03 pts. Manchester United: -0.03 pts.
• 61 min: David Luiz booked for infraction after Chelsea denied free kick. David Luiz booked for coming through the back of Wayne Rooney less than ten seconds after Ramires was fouled in the Manchester United half. Chelsea: -0.03 pts. Manchester United: +0.02 pts.
• 77 min: David Luiz not booked, sent off for challenge on Wayne Rooney. David Luiz deliberately impeded Rooney while off the ball and on a yellow card. Clear second bookable offence. Referee had turned head and did not have a good view. Chelsea: +0.27 pts. Manchester United: -0.26 pts.
• 78 min: Chris Smalling concedes penalty for trip on Yuri Zhirkov. Having just broken up a Chelsea attack, Smalling is caught in possession by Zhirkov, who taps the ball through the defenders legs and tries to go around him, instead tripping over his foot. No dive, but debatable penalty. It's not clear that Smalling could have gotten out of the way. Chelsea: +1.14 pts. Manchester United: -0.74 pts.
• 90 min: Nemanja Vidic not sent off for foul on Didier Drogba. Vidic, already on a yellow commits what appeared to have been a second bookable offence on Didier Drogba by the corner flag. A foul is given but no card is issued.  Chelsea: -0.08 pts. Manchester United: +0.04 pts.

Did I miss anything? Feel free to mix and match whatever you feel was the right/wrong decision. I've just listed some contentious issues and found the value of each. If you're interested in my personal feelings, I think errors were made in minutes 2, 4, 5, 58, 61, 77, and 90, which leads to a grand total of Chelsea getting 0.05 points from Atkinson's dodgy decisions, with United down 0.19 points.

I don't really want to get into an argument over where there were errors and where the calls were right, so I'm totally expecting many people to disagree with what I think the calls should have been. But I think that the above should provide a framework in which to judge Atkinson's effect on the match. The biggest call, clearly, is the Smalling penalty, so it might all just come down to where you stand on that.