Assessment of interpreters' performance has always been in the focus of interest of research on quality in interpretation. As soon as a service is provided it will be evaluated by both the users and the providers of the service, who assess whether the service rendered measures up to their expectations, conscious or otherwise. As a teacher of both the science of interpretation and interpretation as a composite skill, the author not only has a theoretical interest in the insights gleaned from research conducted into he field, she also tries to exploit these findings in her work as an instructor by testing the applicability of established criteria. This article discusses some of the problems the author encountered in this undertaking.