Effectiveness of expert semantic knowledge as a navigational aid within hypertext

Hypertext systems parse documents into content nodes connected by machine s upported links or relationships. Many hypertext researchers claim that the node-link relationships of hypertext provide an information organization th at models the structure of human knowledge and should therefore facilitate information access (Fiderio 1988). Yet, failures of information access occu r when users lack an understanding of the overall scope and organization of a hypertext system (Gay and Mazur 1991). To support this understanding, th e present research incorporated expert-based domain semantics in the design of prosthetic devices for hypertext navigation. The task domain was docume ntation for a word processing system. In the first experiment, the pathfind er algorithm (Schvaneveldt 1990) and cluster analysis were used to identify a set of expert-based semantic relationships between word-processing conce pts. The results from these analyses contributed to the design of two prost heses to assist hypertext navigation: A hierarchical index and a local sema ntic browser. These aids were tested in a second experiment, crossing type of on-line documentation (semantically enhanced hypertext or an alphabetica lly indexed text) with level of subject expertise (novice or expert). Both performance and strategy measures suggest that the semantic prostheses impr oved the accessibility of information for novice users without hampering ex pert performance.