Quantitative concept mapping, in contrast with qualitative approaches, is rigorous scientifically and permits statistical analyses of data about concept learning. This study extends past quantitative research on the structure of student concept learning in pulmonary physiology. Pathfinder scaling is used to derive concept maps for medical and veterinary students and their physiology instructors at Northwestern University and the University of Wisconsin, respectively. The concept maps are evaluated for coherence (internal consistency), student-instructor similarity, and correlation of similarity with final examination scores. Results show that student and instructor concept maps are coherent and that student concept maps become increasingly similar to instructors' concept maps from pre- to postinstruction, but that student-instructor concept map similarity does not correlate with examination performance. Research outcomes are discussed concerning possible sources of variation in student and faculty knowledge structures. ADV PHYSIOL EDUC 23: 72-81, 2000.