An alternative method of measuring the knowledge of students is to use mental models, and specifically concept maps. Concept maps provide a visual representation of conceptual and relationship knowledge within a particular domain. This study builds on previous studies and attempts to reduce their methodological weaknesses. Students in several undergraduate sections of an MIS Telecommunications course were asked to create concept maps of their Telecommunications knowledge at three distinct points throughout the semester. These concept maps were compared across all students at a single point in time, within students across the three time periods, and against the concept map of a domain "expert" at both the individual and composite levels. Findings indicate that the individual and composite maps increased significantly in size over time, and comparisons with the "expert" map show a significantly increasing overlap of concepts over time. Moreover, this study shows the applicability of this technique as an alternate assessment method. Includes seven tables and two figures. (Contains 12 references.) (Author)