Hierarchies are ubiquitous on the web for structuring online catalogs and indexing multidimensional attributed data sets. They are a natural metaphor for information seeking if their levelwise structure mirrors the user's conception of the underlying domain. In other cases, they can be frustrating, especially if multiple drill‐downs are necessary to arrive at information of interest. To support a broad range of users, site designers often expose multiple faceted classifications or provide within‐page pruning mechanisms. We present a new technique, called out-of-turn interaction, that increases the richness of user interaction at hierarchical sites, without enumerating all possible completion paths in the site design. Using out‐of‐turn interaction, the user has the option to circumvent any navigation order imposed by the site and flexibly supply partial input that is otherwise relevant to the task. We conducted a user study to determine if and how users employ out‐of‐turn interaction, through a user interface we built called Extempore, for information-finding tasks. Extempore accepts out‐of‐turn input through voice or text, and we employed it in a U.S. congressional website for this study. Think‐aloud protocols and questionnaires were utilized to understand users' rationale for choosing out‐of‐turn interaction. The results indicate that users are adept at discerning when out‐of‐turn interaction is necessary in a particular task and actively interleaved it with browsing. However, users found cascading information across information‐finding subtasks challenging. By empowering the user to supply unsolicited information while browsing, out‐of‐turn interaction bridges any mental mismatch between the user and the site. Our study not only improves our understanding of out‐of‐turn interaction, but also suggests further opportunities to enrich browsing experiences for users.
Available at: http://works.bepress.com/saverio_perugini/18/