Results improve after a manager is dismissed, and improve about as much for comparable clubs that keep theirs.
Managers are dismissed after an unusually bad run, which is when results were furthest from the club's mean, so improvement was the expected next observation whoever was in charge. Studies matching sacking clubs against clubs in similar slumps that did not sack find little difference. It is regression to the mean with a press conference.
In practice
- A club wins three after a dismissal and the board learns the wrong lesson at some cost.
- A chief executive replaced after a poor quarter presides over a recovery that was already due.