Presented is a study of eighth-grade students' academic problem-solving ability based on their knowledge structures, or their information stored in semantic or long-term memory. The authors describe a technique that they developed to probe knowledge structures with an extension of the card-sort method. The method, known as the Concept Structure Analysis Technique (ConSAT), allows for students to produce graphic structural representations directly, which eliminates the need for statistical procedures to transform data from raw form to graphic form. The advantages of the technique are: (1) having the ability to search for relations between concepts; (2) the ability to analyze structural changes of individuals resulting from instruction; and (3) the ability to search for the integration of more than one kind of structure. (Author/SA)