“…Concept maps can reveal students' knowledge organization by showing connections, clusters of concepts, hierarchical levels, and cross-links between concepts from different levels . Concept map analysis, especially of more constrained forms, has been found to be reliable and valid (Markham et al, 1994;Michael, 1995;Ruiz-Primo et al, 1997, 2001Rye & Rubba, 2002;Shavelson et al, 2005;Stoddart et al, 2000;Yin et al, 2005). Less constrained forms of concept maps can include many different kinds of concepts and connections.…”