Visual decision-making: Using treemaps for the Analytic Hierarchy Process

Abstract

Treemaps graphically represent hierarchical information via a two-dimensional rectangular map, providing the compact visual representations of complex data spaces through both area and color. Their efficiency for particular data searching tasks has been tested through controlled studies with primary benefits seen for two types of tasks: the location of outliers in mass hierarchies and the identification of cause-effect relationships within hierarchies. The analytic hierarchy process (AHP), a decision-making method based upon the division of problem spaces into hierarchies, is visualized through the use of treemaps, which pack large amounts of hierarchical information into small screen spaces. Two direct manipulation tools, presented metaphorically as a “pump” and a “hook,” were developed and applied to the treemap to support AHP sensitivity analysis. The treemap can represent both hierarchical structure and each element's quantitative information simultaneously in a two-dimensional rectangular space; 100% of the designated screen area is utilized.