This paper examines the validity of student evaluation of teaching (SET) in universities. Recent research demonstrates that evaluations can be influenced by factors other than teaching ability such as student characteristics and the physical environment. In this study, it was predicted that students' perception of the lecturer would significantly predict teaching effectiveness ratings. Using an 11-item student rating scale (N = 199), a two-factor confirmatory factor model of teaching effectiveness was specified and estimated using LISREL8; the factors were 'lecturer ability' and 'module attributes'. This initial model was extended to include a factor relating to the students' ratings of the lecturer's charisma. The model was an acceptable description of the data. The charisma factor explained 69% and 37% of the variation in the 'lecturer ability and 'module attributes' factors respectively. These findings suggest that student ratings do not wholly reflect actual teaching effectiveness. It is argued that a central trait exists which influences a student's evaluation of the lecturer.