This thesis contributes to an understanding of the usefulness of and effects from using commenting agents for supporting the use of design knowledge in user interface design. In two empirical studies, we have explored and investigated commenting agents from the aspects of usefulness, appropriateness of different tool behaviour and forms of comments. Our results show a potential value of the commenting approach, but also rais,es several questions concerning the cost and actual effects.
The use of formalized design is considered valuable, yet problematic. Such knowledge is valuable in order to achieve reuse, quality assurance, and design training, but hard to use due to the large volumes, complex structures and weak reference to the design context. The use of knowledge-based tools, capable of generating comments on an evolving design, has been seen as a promising approach to providing user interface designers with formalized design knowledge in the design situation. However, there is a lack of empirical explorations of the idea.
In our research, we have conducted a three-part study of the usefulness of commenting tools. First, a Wizard-of-Oz study with 16 subjects was performed to investigate designers' perceptions of the usefulness of a commenting tool, along with the appropriateness of different tool behaviors and forms of comment. We focus on tool mode (active/passive support) and mood (imperative/declarative comments). Secondly, eight professional designers participated in an interview about support needs. Thirdly, a conceptual design prototype was tested by 7 designers, using cooperative evaluation. A broad set of qualitative and quantitative methods have been used to collect and analyse data.
Our results show that a commenting tool is seen as disturbing but useful (since it affects the user's work situation). Using a commenting tool affects the designer's evaluation behaviour, i.e., there is an indication of some form of knowledge transfer. The short-term result is an increased consciousness in terms of design reflection and guideline usage. In terms of preferred tool behaviour, our results show that imperative presentation, i.e. pointing out ways of overcoming identified design problems, is the easiest to understand. A high perceived mental workload relates to problems detecting comments when using a commenting tool; this means that comments from an active agent risk being overlooked.
In addition, a large part of this thesis can be described as a report of our experiences from using Wizard of Oz techniques to study user interface design support tools. We present our experience and advice for future research.
Linköping: Linköpings Universitet , 1999. , 278 p.