Survival Analysis: Objective assessment of Wait Time in HCl

Waiting for the completion of a system process is an everyday experience. While waiting, a system provides feedback to the user about ongoing processes through temporal metaphors (Progress bar, Busy icons, etc.). One of the key performance requirements for temporal metaphors is to retain the user till the process completes. Researchers have evaluated these metaphors through subjective means, and objective assessment has not been well explored. In this paper, we present survival analysis as an objective assessment method to evaluate temporal metaphors. Through a field experiment, we demonstrate the application of survival analysis and empirically establish that auditory progress bar (a temporal metaphor for audio interfaces) works for callers of a distress helpline. To the best of our knowledge, it is the first study on distress callers. The paper further discusses the applicability of survival analysis for evaluating temporal metaphors and wait time experiments for other applications, tasks, and settings.