This post is the fourth in a series of posts covering projects I worked on before my current postdoc position. Below I have included the abstract for my dissertation, Social Influences on User Behavior in Group Information Repositories. I have produced two papers from my thesis; one was published in CHI 2009, and the other was accepted to CHI 2010.
Rader, E. (2010). The Effect of Audience Design on Labeling, Organizing, and Finding Shared Files. To appear in CHI 2010. 
Rader, E. (2009). Yours, Mine, and (Not) Ours: Social Influences on Group Information Repositories. Proceedings of CHI 2009.
Dissertation Abstract: Group information repositories are systems for organizing and sharing files kept in a central location that all group members can access. These systems are often assumed to be tools for storage and control of files and their metadata, not tools for communication. The storage approach focuses on providing users with detailed information about the objects in the system—where they are, which users have been looking at them, how they’ve been used in the past, etc. However, group information repositories tend to grow and become disorganized over time, such that users have difficulty finding what they need. A different approach is to think of these systems as social tools that could be governed by the same processes as face-to-face communication, like grounding and audience design.
The purpose of this research is to better understand user behavior in group information repositories, and to determine whether social factors might shape users’ choices when labeling and organizing information. While the functionality and capabilities of these systems are essentially the same as the desktop metaphor of personal information management (PIM) systems, I argue that social pressures and processes affect the information structure of the repository, and how it grows and evolves over time. Through a series of interviews with users of a typical group information repository system and an analysis of system log data, I found that users tend to restrict their activities in a repository to files they “own”, are reluctant to delete files that could potentially be useful to others, dislike the clutter that results, and can become demotivated if no one views files they uploaded.
I also conducted a two-part online experiment in which participants labeled and organized short text files into a file-and-folder hierarchy. Eighty-four participants were recruited from two intellectual communities (41 Computer Science graduate students, and 43 Information Science graduate students), such that some participants would share community membership common ground with each other, and some would not. Participants were instructed to organize the files for one of three different audiences: themselves, someone from the same intellectual community, and someone from the other community. Forty-eight participants returned four to six weeks later and completed a series of search tasks, in which they browsed hierarchies created by other participants to find specific files. Including both labeling/organizing and finding tasks in the experiment allowed me to detect potential performance differences when participants searched hierarchies created by others from the same community (or not), and tailored for different audiences. I found that when participants created hierarchies for an audience they imagined was like them, everyone found files in fewer clicks, regardless of whether they were from the same community as the person who created the hierarchy. Further, quantitative analyses of three aspects of the hierarchies (topology, vocabulary, and semantics) helped to explain these results. Users performed better when file and folder labels were more similar to the text of the documents they represented; this correlation was significantly stronger when participants organized the documents for someone who was similar to them.
These results confirm that audience design, a communication process, can in fact impact group information management tasks. The findings from both studies suggest that sharing files via a group information repository is more complicated than simply making them available on a server so that others might access them. My research indicates that processes which have been shown to affect spoken communication also impact word choices when the “interaction” is mediated by a repository. Social factors affect users’ choices regarding how files in the repository are organized and labeled and what information is retained over time; this in turn affects access to information. Knowing that repositories are social systems will allow system designers to incorporate information that makes the users more salient and familiar to each other, so the process of negotiating shared meaning is better supported by the repository system.
