To matrix, network, or hierarchy: That is the question

The authors present a structural analysis of three spatial diagrams-matrice s, networks, and hierarchies-that specifies 10 properties on which these di agrammatic representations are hypothesized to differ: global structure, bu ilding block, number of sets, item/link constraints, item distinguishabilit y, link type, absence of a relation, linking relations, path, and traversal . Each property has a "value" for each diagram, and these property values c onstitute the applicability conditions for the representations. Twenty-thre e college students (computer science majors and math educators) selected th e type of diagram they thought would be most efficient for organizing the i nformation in each of 18 short scenarios and verbally justified the reasons for their selections. The verbal protocols were coded with respect to the structural analysis. Both the representation selection and verbal justifica tion data provided strong support for the structural analysis. Additionally , a factor analysis of students' justifications indicated that the organiza tion of their knowledge is consistent with the structural analysis. Student s' use of the structural properties to select appropriate representations a nd to justify those selections indicates that the structural analysis has p sychological force. (C) 2001 Academic Press.