Liverpool collect detailed data on more than 100,000 players across the world and filter that mind-blowing number down to a few thousand worth close-up analysis. When studying potential signings they use a computer-and-camera process called optical tracking — the same technology used in defence systems to track missiles.

Ian Graham, the club’s director of research, who possesses a Cambridge doctorate in theoretical physics, discussed such methods in a fascinating podcast with Freakonomics Radio. “We get data on every ball touch that every player makes in a game, where it was on the pitch and what happened next. We can see where all the players are at 25 frames per second,” he said. “We try to put everything into one currency. Football is measured in goals,