The key to the "Moneyball" phenomenon: What are the determinants of the level of effort in absence of fi nancial motivation in professional football?

Football provides a rich dataset for the analysis of labour market problems. Of particular interest are situations where the labour market is inefficient. Previously documented by the literature case of football labor market inefficiency, also known as the "Moneyball" effect, led us to the question of how players' incentives work in the absence of financial incentives to exert a particular kind of effort. For football, this type of effort has become the distance covered in a match, which is not valued by the market, but has a positive effect on the likelihood of a team win. To answer the question about player incentives, we identify three groups of factors: motivational, situational, and external, and use data from the 2015-2019 seasons of the German Bundesliga to study the impact of these factors on the level of effort in terms of distance covered. We were particularly interested in studying a non-financial motivation of players; so we hypothesize that players can share the values of the club and its fans by putting more effort into the derby matches that are important for the club. The obtained results allow us to explain the persistence of the "Moneyball" phenomenon over time and to determine the factors affecting the players' choice of unpaid efforts.