The annotators' perspective on co-authoring with structured annotations

In asynchronous collaborative writing, annotations play an important role as a communication medium among co-authors. Research has shown that grouping related annotations together can help those who review an annotated document by reducing their workload and raising the accuracy of their reviewing. Less is known about the impact on users who create such structured annotations — the annotators. The research reported in this thesis had three goals: (1) to better understand current annotation creation practices, (2) to explore how structuring would be used by annotators, both the structuring process and the resulting types of structure, and (3) to evaluate the impact on annotators of having to create structured annotations. We conducted three studies to address each of these goals in turn. The first study was an observational study which strengthened our understanding of how annotators use existing tools to communicate document-related information in the form of annotations. That study revealed annotation practices that could benefit from additional structuring support, such as annotators describing how annotations in a document relate to each other. Our second study used a paper prototype system that supported annotation grouping to investigate how annotators would structure annotations, if given the option. Common behaviour that emerged was the grouping of thematically related annotations, as well as the grouping of annotations specifically targeted to a given co-author. The study also uncovered a range of temporal approaches to structuring annotations, such as top-down and bottom-up grouping. Based on the first two studies, we incorporated a light-weight implicit structuring approach based on tagging into our annotation model and then implemented an extended version of a high-fidelity prototype that supports structured annotation, including tagging. We used the prototype in our third study, a controlled experiment, which compared the impact of structured annotations relative to unstructured annotations. Participants in that study perceived structured annotations to be worth the additional workload required. The study further suggested that the bottom-up grouping approach complements the top-down approach in describing relationships amongst annotations in a document.Science, Faculty ofComputer Science, Department ofGraduat