Because there's nothing sports clubs want more than advice from academics who examine past trends and draw conclusions based on the fact that elite clubs fire people less.
Using data from the inception of the Premier League in 1992 until 2004, which focuses on the short-term and long-term impact of manager change in the top flight of English football, they concluded that 'illusion effects', where the illusion of a short-term reprieve such as when results typically improve following an appointment of a new manager, makes managers and owners believe that things are improving at the club. However, underlying weaknesses and strategic problems, which have not typically been addressed, dictate that performance typically drops to previous standards until problems have been resolved..
The average tenure for a Premiership manager is now 1.38 years, compared to 3.12 years in 2002, with many departures attributed to the fear of relegation to the Football League Championship, which can create a revenue gap of £56- £70 million, according to figures from Deloitte.
Research shows that because of this, there is immense pressure on managers to succeed in the Premier League, with poor results typically resulting in a scapegoating reaction by sacking the manager. Scapegoating theory holds that changing managers will not affect performance and is simply a ritual to apportion blame.
Paul Hughes, from Loughborough University's Business School, believes that the research underlines the desire in top-flight football to achieve instant success.
"Our research illustrates that alongside the obvious examples of Arsenal and Manchester United, those Premiership clubs who retain the services of their manager for a longer period of time are more likely to have successful results. Sam Allardyce's tenure at Bolton Wanderers is an excellent example of this. More recently, David Moyes' tenure at Everton shows how giving managers sufficient time and allowing them time to address the problems within a club can lead to far greater achievements."
Co-researcher and lead author Mat Hughes, from The University of Nottingham, said:
"The research leads us to question how effective sacking a manager really is to teams. Getting rid of the manager means clubs lose a lot of tacit knowledge and although the new manager will quickly change things, those changes might not be the best or right ones.
"Football managers forever state that they need more time in the post to have an effect and our findings show there is much truth to their arguments. It takes time for the managers to reshape the team, its infrastructure, the scouting network, learn about players and the opposition. One of the dangers is that sacking the manager, and the almost inevitable rotation of the coaching staff that goes with that event, causes a lot of important knowledge about the team's strengths, weaknesses, preferences and capabilities to be lost. While the new manager comes in and will quickly seek to reshape the team's style and tactics to suit the new manager's preferred style and ways of doing things, that initial 'shock' does seem to jolt performance away from the rate of decline seen previously.
"Our findings encourage boards and fans to better manage their expectations of the consequences of change. In saying that, we don't dispute that change is often needed — but it should not be a rash response to performance declines."
'Vicious circle theory' posits that changing managers can lead to a decline in performance, because change disrupts well-established processes and brings instabilities and tensions which can have a detrimental effect on results.
The studies suggest that the 'scapegoating approach' of sacking managers early and replacing them in the hope of improved performance is a fallacy, with the Loughborough-research suggesting that manager change may take longer than one year to effect strategic change.
Managers should therefore be given time to improve the club, team and address underlying weaknesses, before any decision to sack them is made. Decisions to sack a manager should be based on their ability to correct weaknesses and thus improve long-term performance, rather than analysing the ratio of wins against results.
Paul added: "Clubs who chop and change their managers — often with no opportunity for the manager to implement real change — tend to experience a long-term downturn in results, even if they have initially experienced success following the appointment of a new manager.
"Our findings suggest that sacking a manager often deflects from the real underlying issues at clubs, which need to be addressed before continuity and success will be achieved."
The research was produced alongside academics from the University of Sheffield and UWE in Bristol.