A just published study from the United States confirms a finding I recall from the US years ago that sacking the coach does not, on average, change the performance of a team.

Professors from the University of Colorado and Loyola University Chicago studied what happened to the records of college football teams that replaced a head coach for performance reasons in the Football Bowl Subdivision (formerly Division 1-A) between 1997 and 2010. Over this period, an average of 10% of FBS teams fired their coach each year because of the team's poor performance on the field.

The authors used statistical methods to compare groups of teams that were similar except for the fact that one set of teams replaced their coach in an attempt to improve performance while the other set of teams did not. They assessed how coaching replacements affected team performance for the four years following a replacement. They found that, on average:

When a team had been performing particularly poorly, replacing the coach resulted in a small, but short-lived, improvement in performance after a change.

The records of mediocre teams - those that, on average, won about 50% of their games in the year prior to replacing a coach - became worse.

The study - Pushing "Reset": The Conditional Effects of Coaching Replacements on College Football Performance -- appears in the journal Social Science Quarterly. It should be made compulsory reading for football club committees.