The influence of hypertext linking structures and task-related variables on information retrieval tasks

Abstract

Hypertext is a method of online information management and/or presentation where textual documents are parsed (modularized) into many nodes and inter-connected using machine-supported links. These systems have become increasingly popular in numerous applications. Unfortunately, few empirical investigations have been conducted concerning the usability and utility of hypertext, and the effusive claims made by many hypertext enthusiasts are largely unsubstantiated.

This study investigated several usability issues relating to hypertext within the context of an information retrieval application. Of particular interest were system linking structures consisting of linear, hierarchical, network, and combination hierarchical/network configurations. These commonly used hypertext linking structures were imposed on a text-intensive geography database (GEO). GEO contains 187 nodes discussing a variety of topics concerning the countries of North Africa. In addition to the linking structures, the task variables of number of required links (to reach the answer) and task type were studied. Task type refers to expert programmers’ judgements as to whether a task is best suited to a hierarchical or network linking structure.

The approach was to create a set of information retrieval (IR) tasks with specific characteristics (as determined by number of required links and task type), and to study the performance of each linking structure in completing these tasks. The intention was to identify the task situations under which each linking structure excels.

Results indicate that hierarchical linking structures perform quite well for most IR tasks and perform significantly better than network linking. The combination condition performs no worse than hierarchical, yet, with the exception of task completion times, provides no consistent advantages over the hierarchical structure. Hence, it is concluded that, for novice users of a system, the performance advantages resulting from the inclusion of network links (in isolation or in combination with hierarchical) are not commensurate with the associated costs of creating such links. Ultimately, results are aimed at a better understanding of hypertext systems, their performance, and more judicious applications of these systems.