Why changing the manager doesn't help much
Fans and boards think that changing the manager can make a big difference, but any effects are short lived. Research by Warwick Business School for the League Managers Association shows that managers following a sacked predecessor enjoy only a brief honeymoon period, largely inspired by the rejuvenation of players looking to impress the new 'gaffer'.
After a dozen games under the new man, results start to tail off. Another six games later and the average points per game is less than his predecessor achieved more than a dozen games prior to his sacking, when the club was probably enjoying some kind of stability.
Since 2000, a new Chelsea manager has won an average of 2.11 points per game after 18 games, compared with the 2.00 points his predecessor was enjoying a dozen or more matches prior to his departure. According to researcher Sue Bridgewater, the one thing that separates Chelsea from other clubs is that the dip in form before its managerial sackings is shallower.
The managerial merry go-round is not confined to the Premier League. The turnover in the Football League's three divisions has been even worse in each of the last four seasons.