Multi-fidelity User Interface Specifications

Specifying user interfaces consists in a fundamental activity in the user interface development life cycle as it informs the subsequent steps. Good quality specifications could lead to a user interface that satisfies the user's needs. The user interface development life cycle typically involves multiple actors possessing all their own particular inputs of user interface artifacts expressed with their own formats, thus posing new constraints for integrating them into comprehensive and consistent specifications of a future user interface. This paper introduces a design technique where these actors can introduce their artifacts by sketching them in their respective input format so as to integrate them into one or multiple output formats. Each artifact can be introduced in a particular level of fidelity (ranging from low to high) and switched to an adjacent level of fidelity after appropriate refining. Refined artifacts are then captured in appropriate models stored in a model repository. In this way, coevolutionary design of user interfaces is introduced, defined, and supported by a collaborative design tool allowing multiple inputs and multiple outputs. This design paradigm is exemplified on a case study and has been tested in an empirical study revealing how designers appreciate it.