A rubric for research theses was developed, based on the manual of the American Psychological Association, to be used as an assessment tool for teachers and students. The aim was to make students aware of what is expected, get familiar with criteria, and interpret teacher and peer feedback. In two studies, it was examined whether students use and value these functions. In the first study, a rubric was provided to 105 Educational Sciences students working on their bachelor's thesis. Questionnaire data indicated that students did value the rubric for the intended functions, although rubric use was not related to ability. In a panel interview, teachers stated that the number of proficiency levels should be increased to be able to distinguish between good and excellent students adequately, and that a criterion concerning student's role during supervision should be added. Therefore, in the second study, 11 teachers were interviewed about their motives to give high grades and about the supervision process. This lead to an extra criterion concerning student's role during supervision and an additional proficiency level to assess excellent performance. It is argued that an adequate course organisation is conditional for the rubric's effectiveness.