Relative subjective count and assessment of interruptive technologies applied to mobile monitoring of stress

A variety of technologies—from agents designed to assist or encourage you, to context-based messaging services—have the opportunity to interrupt you many times throughout the day. One of the challenges with designing new highly interruptive technologies is how to objectively assess their influence on human experience. This paper presents an assessment of a new mobile system that interrupts the wearer to support self-monitoring of stress. We utilize a diverse set of assessment techniques, including a newly proposed measure, relative subjective count, which compares the difference in perceived number of interruptions to actual number of interruptions. This measure, together with direct and indirect subjective reports, and a behavioral choice, is used to evaluate an empathetic version of the mobile system vs. a non-empathetic version. We found that post-experience direct questionnaire assessments such as ‘‘how stressful has using the system been?’’ do not significantly distinguish user experiences with the two systems; however, the new measure of relative subjective count, the behavioral choice, and another indirect questioning strategy, do point toward a preference for the empathetic system. r 2007 Elsevier Ltd. All rights reserved.