In the Donald Duck paperback Football Fever, Gyro Gearlose invents an infallible
referee. This robot-referee, with caterpillar tracks, can decide meticulously whether
a ball has passed the line or not, whether it was offside or not, and so on. It can even
see what is going on behind its back, thanks to hidden cameras on its body. When
players or coaches disagree, the robot-referee sends the images to a giant screen,
so that everyone can see that it was right, as always. Uncle Scrooge McDuck sells
the robot for big money to the football association and Donald is rewarded with
a season ticket; after all, it was his idea and he did teach the robot all the rules!
However, after some weeks, fan attendance drops, a commentator is fired and even
Donald prefers to stay at home instead of going to the Sunday afternoon match.
Pressure mounts and so, before the season comes to an end, the robot-referee is
abolished and everything returns to normal; that is, the fans, players, commentators,
and coaches return to their quarrelling over the referee’s controversial decisions.
The grain of truth in the story is that a perfect, infallible referee is not necessarily an
improvement for soccer. My claim is that due to the notoriously erratic performance
of referees in soccer, CB is higher than it otherwise would be, provided errors are
made in an impartial way. Intuitively, a referee making random errors produces
noise that disturbs the outcome of the match towards a more balanced outcome than
would be the case where the outcome is only determined by relative team qualities.
If referees tend to be “homers” – deciding on average in favour of the team playing
at home – then the effect of the fallible referee is likewise the home advantage
effect, which is also conducive to CB. Only if referees are on balance favouring the
stronger teams might the introduction of a fifth official with a monitor improve the
level of CB.8