Concept mapping, a technique of graphically representing concepts and their relationship, was used to assess changes in the structural knowledge of prospective teachers at three levels of a teacher education program. The concept "teacher planning" was mapped at the beginning and end of the semester by 49 students in introductory, intermediate, and advanced undergraduate courses in teacher education. Scores calculated included: (1) item scores; (2) level scores; (3) similarity to group and instructor scores; and (4) item stream similarity to instructor scores. Content analysis was compared with instructors' intentions for student concepts. Both qualitative and quantitative analysis indicated that student maps became more differentiated and organized, with evidence of development of a shared vocabulary between instructor and student. Concept maps provide an overview of student thinking on a concept. A sample concept map is attached. (SLD)