This article examines the way assessor produces evaluative judgments about dynamical and complex practices. It questions the place of spontaneous attribution of values in formal evaluations. This empirical work focuses on referees’ supervision as it occurs during a match. This study identifies four processes of local evaluations and it distinguishes two types of global evaluations : on one hand evaluations based on the appreciation of local evaluative judgments, on the other hand evaluations based on a priori indicators. The supervisor incorporates the dynamic of the practice into his evaluation : by leaving open some local judgments and by constructing global judgments taking over prior judgments. This work also highlights that evaluating ...