The Complexity of Team Cohesion

Originally Written: August 2016

Ben Darwin, the former Australian rugby international, now runs his own sports consultancy, Gain Line Analytics. The main focus of his work is team cohesion which he measures by his own trademarked metric, the Team Work Index (TWI). Ben has found that TWI accounts for as much as 40% of on field performance. I had a long Skype call with Ben when he was just starting out as an analyst and found him to be very personable and knowledgeable. His experience in elite team sport gives him a real insight into the dynamics of team building and how to create (and destroy) that critical sporting intangible, team spirit.

I don’t know exactly how Ben defines team cohesion (TWI is his intellectual property) but I am pretty sure that fundamentally it must be a measure of how much time that players on a team have played together, what I would call team shared experience (TSE). The relationship between TSE and team performance has been the subject of several academic studies. One of the first on the subject was published in 2002 by Berman et al. who used basketball data and found a significant link between TSE and team performance in the NBA. Along with my co-author, Andy Lockett, I have just published a study in the Journal of Management Studies using data from the FA Premier League over the ten years, 1996 – 2006, and we also found that TSE was a significant driver of team performance.

A significant link between TSE and team performance is no surprise. The difficulty arises in unravelling the multitude of factors influencing team performance. The analytical problem is necessarily a multivariate one with the estimated impact of TSE on team performance crucially affected by how you control for team quality as well as the dynamics and feedback effects. Increased TSE will improve team performance but better team performance can mean higher TSE in the future as teams try to retain a successful squad. The relationship runs both ways. And, of course, the added complication is that the richest teams have the financial power to be better able to recruit and retain top quality players. But how much of their success is down to recruiting the best players and how much is down to building team cohesion between these top players? That in turn raises the question of the role of the coaching staff in integrating a group of individual players both tactically and emotionally. It follows that the coaching input should also be included as a driver of team performance. Modelling all of these possible factors is a very complex analytical problem but crucial to producing insights into team performance that have practical relevance. No wonder that it took Andy and myself nearly ten years to complete our research and get it published in a top academic journal.

The most important finding of our model of team performance in Premiership football, after controlling for team quality using wage costs as well as average team age and career experience, is that it is not player TSE on its own that has the most significant impact on team performance. Rather it is the interaction of player TSE and the length of time that the head coach has spent with the team (i.e. coach TSE). In other words, it is the shared experience of players and coaches together than drives performance. And the effect remains strong even after allowing for the dynamics of team performance across seasons (i.e. momentum effects) as well as the previously discussed feedback effects. There is a complex interaction between player TSE and coach TSE as shown in Figure 1 below which uses three different scenarios – low player TSE, moderate player TSE and high player TSE – to illustrate how the impact of an increase in player TSE on team performance changes as player TSE increases and as coach TSE increases. The biggest impact of building team cohesion occurs when teams have relatively low levels of player TSE, and the impact increases the longer that the coach has been with the team.

Our model of team performance captures very well the trade-off facing teams when they recruit new players. Signing players of higher quality will increase team quality but will reduce team cohesion. Player turnover is a double-edged sword when player TSE is so important. And the same goes for changing the head coach which immediately wipes out all of the player-coach TSE. The new head coach will start with zero shared experience with the existing squad. Our model actually shows that the negative disruption effect of a new coach will be highest when the team has a high level of player TSE. A group of players who have been together for a long period may be particularly resistant to the changes introduced by a new coach as well as potentially reacting negatively to the increased uncertainty about their status in the team.