Web-based Visualization Interface Testing: Similarity Judgments

TouchGraph is a Web-based ranked similarity list browser that visualizes the relationship between the query and resulting item set as a graph. TouchGraph provides visual analogs to Amazon's recommendation feature based on item similarity and Google's "similar to" pages. TouchGraph may be able to assist diverse Web users, who have varying levels of knowledge on search topics, to visually select similar items to their query. To examine this assumption further, this investigation asks: what are the effects of topic knowledge level on the similarity judgments generated by the users in comparison to the visualized system depictions? Seventeen participants were asked to use TouchGraph for similarity matching of search output to the query and their results were compared to the items shown as most similar to the query by the visualization. The results showed that participants rated their topic knowledge level quite low for most tasks, there was a high degree of participant-system item selection overlap, and a statistically significant relationship was found between knowledge level and node use for half of the tasks. The subjective satisfaction data were positive for the TouchGraph interface. The findings suggest that the TouchGraph visualization has the potential to enhance Web search effectiveness. This study aids in understanding better system design issues in regard to visualization-based tools for Web information retrieval.