Expectations as Reference Points: Field Evidence from Professional Soccer

We show that professional soccer players and their coaches exhibit reference-dependent behavior during matches. Controlling for the state of the match and for unobserved heterogeneity, we show on a minute-by-minute basis that players breach the rules of the game, measured by the referee's assignment of cards, significantly more often if their teams are behind the expected match outcome, measured by pre-play betting odds of large professional bookmakers. We further show that coaches implement significantly more offensive substitutions if their teams are behind expectation. Both types of behaviors impair the expected ultimate match outcome of the team, which shows that our findings do not simply reflect fully rational responses to reference-dependent incentive schemes of favorite teams falling behind. We derive these results in a data set that contains more than 8'200 matches from 12 seasons of the German Bundesliga and 12 seasons of the English Premier League.