Measuring the success of knowledge transfer from universities to firms has traditionally been seen as an unproblematic activity, apart from the practical issues of how to measure the new jobs and sales that have been created. This paper problematises the concept of ‘success’ in terms of its definition, measurement and interpretation. It explores critically one approach to policy evaluation by assessing a programme of knowledge transfer to SMEs using university students. It reviews critically different definitions of success and methods of assessing success. It provides guidance on how to predict success, which may be useful for other programmes of knowledge transfer. An agenda for future research in this area is proposed that links this paper’s approach to other methods of evaluation.