An empirical study of Web site navigation structures' impacts on Web site usability

Web sites are intended to facilitate knowledge acquisition, often in the interest of supporting decision making. Based on a taxonomy of factors influencing Web site usability, hypotheses are developed about usability of alternative navigation structures. These hypotheses are tested via experiments that measure user performance in accomplishing knowledge acquisition tasks and user perceptions of usability. Two rounds of experimentation are performed for both simple and relatively complex task sets. Results show that a usage-oriented hierarchy or a combined hierarchy is a navigation structure associated with significantly higher usability than subject-oriented hierarchies, for both simple and relatively complex knowledge acquisition tasks.