Towards an Evaluation Framework

Reducing workload in a UI while still letting users feel in control is not trivial. This workload/control tradeoff is described in the literature and deserves attention in design practice. However, there is no evaluation framework for it supporting both explicit and implicit measurement, mainly because measuring sense of control implicitly is just difficult. A recently proposed implicit evaluation methodology – measuring sense of agency via interval estimation – seems promising and calls for further investigation. We studied its feasibility in a continuous control task – cinematographic camera motion – and compared a multi-touch software joystick to a mid-air gesture UI (N=8). Data was collected both explicitly and implicitly. Our results suggest that the mid-air gesture design does not increase the sense of agency. Both methodologies yielded similar results but the implicit one was more sensitive and the combination of both led to convincing overall results.