Tuesday, December 13, 2011

Academic Reasearch on Premier League Managers

At the top of the managerial heap,
no matter how you cut it...

I came across an interesting research paper last week courtesy of fellow statto Paul Tomkins.  It's entitled The Performance of Football Club Managers: Skill or Luck? and is authored by Adrian R. Bell, Chris Brooks, and Tom Markham.  All three are attached to the ICMA Centre at the University of Reading's Henley school of business.  In the paper the three examine which Premier League managers over and under perform when a number of factors (injuries, suspensions, extra games, transfer spend, wages, etc.) are taken into account.  The paper is a fascinating revelation of managerial performance.  If you can get access to the full text, I highly recommend a read of it.  Some of the highlights include:
  • Based upon the researchers' model, managerial over and under performance can be evaluated by their tenth match in charge of a club.
  • The authors found that net transfer spending year-to-year is not a statistically significant predictor, but readily admit this is likely due to the fact that they do not account for the cumulative effect of transfer spending year-over-year.  This was a criticism I made of the similar conclusion in Soccernomics, and one I've routinely addressed via models based upon the Transfer Price Index which doe take such year-over-year benefits in transfer spending into account.
  • The authors note that a team increasing their wage bill by £100M equates to an increase of 0.8 expected points per match.  Given the 2009/2010 wage bills in the Premier League, only one team was capable of such a gap against more than half of the teams (Chelsea) as the median wage bill was £54M.  Most teams competed with much less of a financial advantage within a match.
  • It turns out the total number of matches played is significant in one direction and insignificant in another (you'll have to read the paper to get the details).  The authors observe several reasons for the dichotomy, and mention that "large number of non-league games are only an issue for teams that are successful in those competitions..." This is a similar criticism I have made of MLS's playoff format and how it penalizes teams that are successful in non-league competitions.
  • At the top of the managerial heap, even when factoring in the expectations that come with player wages, availability, and transfers are Alex Ferguson, Guus Hiddink, Arsene Wenger, Jose Mourinho, Rafa Benitez, Sam Allardyce, David Moyes, Steve McClaren, and Martin O'Neill.  These men get/got the most out of what was available to them.
  • The authors identify Steve Wigley (Southampton 2004/05), Mick McCarthy (Sunderland 2005/06), and Aidy Boothroyd (Watford 2006/07) as managers who under performed early enough in their tenures that that should have been sacked much earlier than they eventually were.
  • There are also a number of other managers singled out as being sacked when such a sacking wasn't warranted by the authors' model.  Included in this group are Glenn Roeder (Newcastle United 2006/07), Chris Coleman (Fulham 2006/07), Martin Jol (Tottenham 2007/08), Avram Grant (Chelsea 2007/08), and Sven-Goran Eriksson (Manchester City 2007/08)
Statistical models won't ever override the passions of the supporters or the demanding nature of owners who want trophies sooner rather than later.  Perhaps they can at least inform decision makers as to when such passions are warranted or unwarranted, especially when the tools at a manager's disposal are taken into consideration.  Sackings and constant changes in managerial direction can be very disruptive to everyone's end goal of championship glory.  This paper contributes much to that understanding - I highly recommend giving it a read.

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