Abstract The goal of this study is to understand whether providing a search intermediary familiar with a problem domain and its topical structure would support a user's Web searching tasks, especially complicated tasks with multifaceted topics, and whether the order of searching tasks or system usage influences their successful completion. This study investigates the effect of two factors, the interaction mode and the display layout, on the three main measures of the user's Web searching behaviors: effectiveness, efficiency, and usability. Two interaction modes are compared, mediation via a domain‐specific document collection versus nonmediated search, and two display layouts, a combination of browsing‐supporting hierarchic display and ranked list of results versus the simple linear list of search results. The results are analyzed in the Flow theory point of view; they were analyzed by order of the tasks and system usage order. The findings of this study contribute to a better understanding of how the mediation system and/or the combined display support a Web information user.

This paper reports on and discusses a set of user experiments using the TREC 2003 Web interactive track protocol. The focus is on comparing humans and machine algorithms in terms of performance in a topic distillation task. We also investigated the effect of the search results layout in supporting the users' effort.We have demonstrated that machines can perform nearly as well as people on the topic distillation task. Given a system tailored to the task there is significant performance improvement and finally, given a presentation that supports the task, there is strong user satisfaction.

Abstract Clear and precise queries are a necessity when searching very large document collections, especially when query‐based retrieval is the only means of exploration. We propose system‐mediated information access as a solution for users' well‐documented inability to formulate good queries. Our approach is based on two main assumptions: first, on the ability of document clustering to reveal the topical, semantic structure of a problem domain represented by a specialized “source collection,” and, second, on the capacity of statistical language models to convey content. Taking the role of the human mediator or intermediary searcher, a mediation system interacts with the user and supports her exploration of a relatively small source collection, chosen to be representative for the problem domain. Based on the user's selection of relevant “exemplary” documents and clusters from this source collection, the system builds a language model of her information need. This model is subsequently used to derive “mediated queries,” which are expected to convey precisely and comprehensively the user's information need, and can be submitted by the user to search any large and heterogeneous “target collections.” We present results of experiments that simulated various mediation strategies and compared the effect on mediation effectiveness of a variety of parameters, such as the similarity measure, the weighting scheme, and the clustering method. They provide both upperbounds of performance that can potentially be reached by real end users and a comparison between the effectiveness of these strategies. The experimental evidence suggests that information retrieval mediated through a clustered specialized collection has potential to improve effectiveness significantly.

Query length in best-match information retrieval (IR) systems is well known to be positively related to effectiveness in the IR task, when measured in experimental, non-interactive environments. However, in operational, interactive IR systems, query length is quite typically very short, on the order of two to three words. We report on a study which tested the effectiveness of a particular query elicitation technique in increasing initial searcher query length, and which tested the effectiveness of queries elicited using this technique, and the relationship in general between query length and search effectiveness in interactive IR. Results show that the specific technique results in longer queries than a standard query elicitation technique, that this technique is indeed usable, that the technique results in increased user satisfaction with the search, and that query length is positively correlated with user satisfaction with the search.

No abstract available.

No abstract available.