On the same two variables, time and operational errors, the Venn diagram mode performs better than conventional boolean retrieval. Threads in a query sequence describes the continuity during retrieval. Sequences of tactics concern the combined mode and describe how different retrieval modes succeed each other as the retrieval process evolves. The authors report on an experiment in retrieval interface performance. Subjects were given various tasks to perform using the four modes.
Several results are surprising.
Browsing tended to work well or not at all. Paper manuals outperformed automated means. Subjects preferred the Venn presentation to the logical expression interface, and performed better using it. The bulk of the paper describes experimental conditions, results, and their interpretation. These include some factors that may limit the overall applicability of the work.