http://www.bbc.co.uk/sport/football/38684434

Opta allegedly have a database of quarter of a million shots which, supposedly, can predict whether a goal should be scored or not. According to this database, Marshall should have conceded 26 goals there, yet conceded 37. In other words, he conceded 11 more than he was expected to - the worst of any PL keeper who has faced more than 100 shots.