The cost-of-knowledge characteristic function: display evaluation for direct-walk dynamic information visualizations

In this paper we present a method, the Cost-of-Knowledge Characteristic Function, for characterizing information access from dynamic displays. The paper works out this method for a simple, but important, class of dynamic displays called direct-walk interactive information visualizations, in which information is accessed through a sequence of mouse selections and key selections. The method is used to characterize a simple calendar task for an application of the Information Visualizer, to compute the changes in characterization as the result of possible program variants, and to conduct empirical comparison between different systems with the same function.