A new approach to teaching method assessment using student focused qualitative studies and the theoretical framework of mental models is proposed. The methodology is considered specifically for the advantages it offers when applied to the assessment of inquiry-based teaching methods. The theoretical foundation of mental models is discussed, and the framework described in detail, with examples from preliminary experimental results. It is argued that the application of this methodology provides a more learner focused approach to assessing a teaching activity, which provides more detail about the relevant cognitive processes used by the student and is a better guide for improving the activity. (Contains 1 table.)