A model for notification systems evaluation—assessing user goals for multitasking activity

Abstract

Addressing the need to tailor usability evaluation methods (UEMs) and promote effective reuse of HCI knowledge for computing activities undertaken in divided-attention situations, we present the foundations of a unifying model that can guide evaluation efforts for notification systems. Often implemented as ubiquitous systems or within a small portion of the traditional desktop, notification systems typically deliver information of interest in a parallel, multitasking approach, extraneous or supplemental to a user's attention priority. Such systems represent a difficult challenge to evaluate meaningfully. We introduce a design model of user goals based on blends of three critical parameters-interruption, reaction, and comprehension. Categorization possibilities form a logical, descriptive design space for notification systems, rooted in human information processing theory. This model allows conceptualization of distinct action models for at least eight classes of notification systems, which we describe and analyze with a human information processing model. System classification regions immediately suggest useful empirical and analytical evaluation metrics from related literature. We present a case study that demonstrates how these techniques can assist an evaluator in adapting traditional UEMs for notification and other multitasking systems. We explain why using the design model categorization scheme enabled us to generate evaluation results that are more relevant for the system redesign than the results of the original exploration done by the system's designers.

Collision warning design to mitigate driver distraction

“…This study fills an important gap in our understanding of how the display parameters of a specific type of notification system, a warning, influence performance and acceptance [18]. The results point to the importance of considering interface characteristics in addition to the algorithms that trigger the warnings.…”

Ambient Timer – Unobtrusively Reminding Users of Upcoming Tasks with Ambient Light

“…McCrickard and Chewar describe notification systems as "interfaces specifically designed to support user access to additional digital information from sources secondary to current activities" [17]. While notification systems may often be distracting, this behaviour is usually tolerated by users [18]. Fogarty et al report on the development of a sensor-based system to better automatically predict interruptability of human users [9].…”

Picking Up Artifacts: Storyboarding as a Gateway to Reuse

“…Notification systems are designed to be used in dual-task situations in which a user engaged in a primary task needs to be interrupted for a reason [14]. Some of the design problems we assigned involved notifying nuclear plant operators of changing core temperatures, passengers in airports of flight status changes, commuters of empty parking lot spots while driving, theme park visitors of ride wait times, and students of empty spots for classes they wish to register for.…”