What Difference Does A New Manager Make?

Whilst reading Simon Kuper and Stefan Szymanski’s phenomenal book Soccernomics I was amazed by one chapter; Do managers' matter?

The line intrigued me. For a position of huge importance, managerial changes in football occur incredibly quickly – looking from the outside they do… decisions clearly take longer behind closed doors – compared to jobs in comparatively important business-world positions.

Managers are seen as the figureheads of the club but they are replaced so easily and so often that it seems anyone can do the job for a short period. So do they matter? I wanted to know what effect a new manager would have on a club when taking over and if they had a huge influence on a clubs position in the table or whether it was the quality of the player.

Therefore, I started trawling through data to see whether these managerial changes make as substantial a difference as we’re led to believe. I analysed the data of managerial changes over the last five Premier League seasons in the hope of finding out whether making a managerial change actually benefitted anyone.

The focus was on the time between the previous manager leaving his post and the new manager taking charger whilst also looking at the difference in league position from when the manager left and the position at the end of the league season.

In cases where a manager left at the end of the season in pre-season, the end of season position obtained by the new manager was compared to the position the previous manager left the club in at the end of the previous season.

During this article we will look at;

• Trends of managerial changes
• The best (and worst) clubs for managerial changes
• When is the best month to make a managerial change?
• How long is the correct waiting period?
• What the total managerial difference is

Trends of managerial changes.

Firstly, we’ll look at how managerial changes affected a clubs position per season from the 2009/10 season to the 2013/14 season:

Positional changes after managerial changes per season

Recent trends suggest Premier League clubs are actually getting better at deciding when to change manager. In fact, the most recent season – 2013/14 – featured the most managerial changes of any season within the data with an impressive 14 changes. This makes a positive positional difference of +7 even more extraordinary. 

The second highest positive positional difference was also the season with the second most managerial changes with 12 changes. The season with the lowest positional difference was 2011/2012 with a positional difference of -11. Interestingly, this was also the season with the fewest managerial changes with a paltry seven managerial changes thus destroying the notion that less is often more.

The best (and worst) clubs for managerial changes

Rather than quantity of changes, the focus should be on the quality of the managerial change. Some clubs are better at this than others. 

To look at which clubs were more competent with managerial changes, I took the data of the last five Premier League seasons and added up the total positional differences from each club after each individual managerial change.

Positional changes after managerial changes for each club

The graph above shows each team in the Premier League in the last five seasons who have had at least one managerial change (thus excluding you Arsenal, Birmingham and Blackpool).  The teams in yellow had more than one managerial change during the period with the teams in red having a single managerial change. 

The graph shows us that clubs rarely make a sizeable difference in the proceeding season; however, there are some anomalies in the data. For instance, Aston Villa. During the previous five premier league seasons, Aston Villa have made a total of 3 managerial changes. Martin O’Neill left to be replaced by Gerard Houllier resulting in a ‘-3’ shift in position. 

Houllier was then replaced by Alex McCleish and we all know what happened there; a ‘-7’ shift in position totalling a whopping ‘-10’ shift in position since the depature of Martin O’Neill. Finally, in some positive news for Villa fans, the decline was halted by the appointment of Paul Lambert to replace McCleish which ended in a ‘+1’ positional change. Well, every little helps!

On the opposite end of the scale, Sundeland seem to be the undisputed masters of the managerial change. With four  managerial changes – second to only Chelsea in total changes – Sunderland have changed manager often yet effectively. A massive total of +11 positional change is a stat to be impressed by.

The first change was Ricky Sbragia leaving his post to be replaced by Steve Bruce and resulting in a ‘+3’ difference in position. Bruce then left the club to join Hull City and was replaced by Aston Villa miracle worker Martin O’Neill who ensured yet another positive positional change of ‘+3’. O’Neill’s magic soon wore off as he was replaced by the enigmatic Paolo Di Canio who proceed over the only negative positional change for a Sunderland manager in the data range suffering a ‘-1’ positional change.

Finally, Di Cano left the club and was replaced by Gus Poyet. After, a rollercoaster season fighting relegation, Poyet led the club to 14^th place and a ‘+6’ positional change.

As impressive as the stat is, Sunderland are yet to finish higher than 10^th in the table (under Steve Bruce) in the five years of data.

In terms of individual changes, the embarrassment of worst managerial change in terms of positional change belonged to Alex McCleish at Aston Villa. A campaign that Villa fans will remember for a long time. On the opposite end of the scale, the best change belonged to Tony Pulis who guided Crystal Palace to 11^th position after taking over from Ian Holloway who had left the club languishing in 19^th place. A huge ‘+8’ change in position. Talk about an impact!

When is the best month to sack a manager?

The saying goes that the best time to replace a manager is during pre-season in order to give the manager a chance to bring in his own players and ensure the club is playing in the style they demand. How true is this though?

To answer this question, I looked at the months in which managers were sacked and added a positional change total to look at which month provided the highest positional change for clubs and which month provided the lowest positional change.

The graph below shows the total positional changes for each month;

Positional changes per month after managerial changes

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
3	4	-2	0	4	-16	-2	-3	6	8	3	-5

Myth. Busted. Pre-season lasts for June, July and August. The total positional change from the previous season to the end of the next season for managerial changes? -21. Minus 21 places for managerial changes in pre-season. That would mean relegation for even the champions of the league.

The most positive changes occur in September and October with a ‘+6’ and a ‘+8’ positional change respectively. Managerial changes in September and October are likely after a disastrous start to a season where the team is performing exceedingly below expectations. Therefore, a new manager is installed and has the longest possible time to make changes to the clubs personnel and on-field performances to bring them back to their expected level or higher.

The largest anomaly in the given data is the month of June. There were seven appointments in June in the five years of data and a positional difference of ‘-16’ thus giving an average of ‘-2.3’ positional change per managerial appointment. The data involves the biggest negative managerial change in the data of ‘-7’ belonging to Alex McLeish of Aston Villa which distorts the data. However, a manager has three months before the season starts when appointed in June and should therefore have the best chance to make an impact on the team.

What is the correct waiting period for a managerial change?

At the start of the article I referenced a chapter in the book Soccernomics. The chapter queried whether managers matter which led to me thinking that managerial changes are often made extremely quickly for what is viewed as an ‘important’ figurehead position at a club. 

This got me thinking. How long exactly should a managerial appointment take to maximise the potential success? The mind instantly says a decision should be made within days to ensure that no days are wasted and potential points dropped in upcoming fixtures.

However, the data suggests otherwise:

Positional changes based on the time spent between managerial changes.

I collected the data by looking at how long each club took between the previous manager leaving and the new manager being appointed and the subsequent positional change achieved by the new manager. The results are illuminating.

There were 22 instances of managers being replaced in under a week and the grand total of all 22 instances was zero. So, when a manager is replaced within a week of his predecessor leaving, on average he performs no better thus making the change a pointless exercise. Within the 22 instances there was examples of huge differences both positively ‘+6’ and negatively ‘-6’ but on average, no difference was made.

Then we go onto changes made after three weeks or more. When a club waited three weeks to a month to make a change the eventual positional change was a soul-destroying -8 places. For most clubs, this would end in relegation as a team would generally not make a change unless in the lower reaches of the division. So why does waiting so long make such a negative difference? One theory is that in a general three week period, a club will play around three or four games. That’s 12 points that they could pick up or other teams could pick up while a caretaker manager is in control of the team. When a new manager eventually comes in, they will be the third manager – possibly with a third philosophy that the players will have to learn – in the space of a month. Not ideal for positional improvement in the table.

So, when should a managerial change be made? Anytime over a week and under three weeks in order to reap maximum benefits. This ensures a waiting period that allows reflection and finding the ideal candidate without missing too many opportunities to pick up points. When a club waiting 2-3 weeks, they picked up five positions in the table. Five positions is huge. Finishing higher up the table is huge financially and psychologically. A higher position will allow for better players to be bought due to the financial rewards on offer.

There you have it, if your club appoints a manager within a week, expect no difference in results. If they wait over three weeks, be prepared for a rough ride to come. However, if your club waits 2-3 weeks? There will be joys to come.

What is the total positional difference after a managerial change?

Throughout this article we’ve established what month is best to make a managerial change and which the worst is. We’ve worked out Sunderland are extremely good at making managerial changes whilst Aston Villa are downright terrible. 

We’ve also seen that making a managerial change with a waiting period of less than seven days makes no difference whatsoever whilst waiting longer than three weeks is to the detriment of your clubs chances of progression.

Finally, we get down to the most important stat of all, the total positional difference for managerial changes in the premier league:

0.

Yes, that’s correct. Over the last 5 years, the overall positional difference after a managerial change is exactly ZERO. Changing a manager will have a different effect for each club – just ask Aston Villa or Sunderland fans – but in the grand scheme of things with each club’s positional difference totalled together the effect is utterly pointless.