Effects of link annotations on search performance in layered and unlayered hierarchically organized information spaces

The effects of link annotations on user search performance in hypertext environments having deep (layered) and shallow link structures were investigated in this study. Four environments were tested—layered-annotated, layered-unannotated, shallow-annotated, and shallow-unannotated. A single document was divided into 48 sections, and layered and unlayered versions were created. Additional versions were created by adding annotations to the links in the layered and unlayered versions. Subjects were given three queries of varying difficulty and then asked to find the answers to the queries that were contained within the hypertext environment to which they were randomly assigned. Correspondence between the wording links and queries was used to define difficulty level. The results of the study confirmed previous research that shallow link structures are better than deep (layered) link structures. Annotations had virtually no effect on the search performance of the subjects. The subjects performed similarly in the annotated and unannotated environments, regardless of whether the link structures were shallow or deep. An analysis of question difficulty suggests that the wording in links has primacy over the wording in annotations in influencing user search behavior.