Perceptions of the legitimacy of the courts are generally measured by means of surveys among the population. As legitimacy is an abstract concept, it has to be captured by simple questions. The questions posed in influential surveys use a variety of conceptualisations. Instead of asking for opinions about legitimacy, one can also examine whether the acceptance of the legitimacy of the courts is demonstrated by behaviour. This offers potentially a more reliable way to measure legitimacy: not by what people say but what they do. In this article, drawing on the conceptualisation of legitimacy in surveys, behavioural effects are derived. It would be preferable to measure these behaviours directly, but in the absence of such data we have to make do with observed behaviour. A study is presented on the legitimacy of the judiciary in European countries, based on observations by judges. It is a first step, but the results are different from and more insightful than surveys of citizens
