Students on one-year full-time Master's programmes, particularly those studying in English for the first time, or after a break from studies, can struggle with the demands of an academic essay. This study reports the evaluation of the introduction of the use of concept maps as a learning and assessment tool, designed to support students' transition into postgraduate taught study at a UK university. The mixed methods case study draws on interviews with students (19), academic teaching staff (9) and secondary analysis of course assessment data from the previous five years. We found that while staff and students reported that concept maps supported learning and helped students overcome barriers, the quantitative analysis showed no significant change in students' attainment. We discuss possible reasons for this, and ways in which the concept map as assessment task may be developed.