Contract situations, somewhat like the one Cech found himself in, are the subject of a recent paper by Daniel Weimar and Katrin Scharfenkamp. Published in Managerial and Decision Economics, the paper examines the effort that football players spend on behalf of their current team when they have already signed a contract to play for another team. The authors found a statistically significant 1.23% reduction in effort by such individuals. Crucially, this did not translate into a statistically significant reduction in team performance.
Weimar and Scharfenkamp measure effort using the distance the player runs during a game (hardly a measure useful for goalkeepers like Cech). One of the more interesting elements of the paper is the discussion of why this measure was selected. For example, the authors note that the correlation between the distance covered by a player and the market value is low (r = -0.03). In addition, the authors go to great lengths to control for all sorts of potential other influences.
Establishing a measure of individual contribution to team performance is not easy. And it can be more difficult in some sports than others. On the surface, one would imagine that the individual contribution is easier to identify in a sport like baseball than football. Yet, it is not straight forward in baseball as another recent paper by Heather O’Neill and Scott Deacle explains. Published in Applied Economics, the O’Neill and Deacle paper spends a fair deal of time explaining why the authors chose on-base-plus-slugging percentage as their measure of individual effort. This paper also presents evidence to show that there is a relationship between a player’s contract position and their effort. Players show improved performances in the final year of their contract.
Both papers present impressive amount of data. One of the features of sport is that sports performances tend to be public and measurable. The accumulation of evidence makes it is hard to deny that there is some systematic variation of a player’s performance and that this is related to their contract. It is less clear whether this variation is priced into the contract. Or, as Joel Maxcy and others have noted in the literature, maybe the contracts are structured in such a way to deal with such situations.