Abstract. Research in ambient intelligent systems faces a challenging endeavor, namely the evaluation of user experience of ambient displays. Due to the fact that ambient displays should be unobtrusive, it is hard for users to appraise them on a reflective level (i.e. interviews and questionnaires). In this paper we present a methodological approach that combines an implicit (the Affect Misattribution Procedure (AMP)) and an explicit measurement technique (questionnaire for the persuasive effect (PeQ)) to tackle this problem. We used this approach in a study of an interface (Operator Guide) that provides information to operators in a semiconductor factory. Results show that the implicit technique is better suited to assess fine attitudinal differences on how users experience the display than explicit questionnaires. However, explicit measures are valuable to gain suggestions for improvements and thus it is concluded that this method triangulation adds value for the research on ambient persuasive interfaces.