No abstract

The distinction between field and laboratory is classical in research methodology. In human-computer interaction, and in usability evaluation in particular, it has been a controversial topic for several years. The advent of mobile devices has revived this topic. Empirical studies that compare evaluations in the two settings are beginning to appear, but they provide very different results. This paper presents results from an experimental comparison of a fieldbased and a lab-based usability evaluation of a mobile system. The two evaluations were conducted in exactly the same way. The conclusion is that it is definitely worth the hassle to conduct usability evaluations in the field. In the field-based evaluation we identified significantly more usability problems and this setting revealed problems with interaction style and cognitive load that were not identified in the laboratory.

This paper reports from an exploratory study of means for providing feedback from a usability evaluation to the user interface designers. In this study, we conducted a usability evaluation of a mobile system that is used by craftsmen to register use of time and materials. The results of this evaluation were presented to the designers in different forms. First, the designers were presented with a traditional usability report. Second, we facilitated a dialogue where the results of the evaluation were discussed. During this process, we collected opinions from the designers on the main strengths and weaknesses of the system. The findings indicate that detailed descriptions of problems and log descriptions of the user's interaction with the system and of system interaction are useful for the designers when trying to understand the usability problems that the users have encountered.

Designing a user interface is often a complex undertaking. Modelbased user interface design is an approach where models and mappings between them form the basis for creating and specifying the design of a user interface. Such models usually include descriptions of the tasks of the prospective user, but there is considerable variation in the other models that are employed. This paper explores the extent to which the notion of interaction space is useful as an abstraction mechanism to reduce the complexity of creating and specifying a user interface design. We present how we designed a specific user interface through use of design techniques and models that employ the notion of interaction space. This design effort departed from the task models in an object-oriented model of the users' problem and application domains. The lessons learned emphasize that the notion of interactions spaces is a useful abstraction mechanism that can help user interface designers exploit object-oriented analysis results and reduce the complexity of designing a user interface.

Communication and coordination of mobile and distributed work activities is a challenging application domain for mobile handheld devices. In this paper, we present the design of a mobile system to support communication and coordination between workers in safety-critical tasks in a power plant. The design of the system was based on ideas inherited from a communicator that was developed for a different application domain. The design was devised through a combination of ethnography and object-orientation. The mobile system we designed provides location-aware access to computerized information and process control on a handheld wireless computer terminal.