Development of E-mail Delivery Mediation System Based on Interruptibility and Its Evaluation in Daily Office Work Scenario

Notifications of e-mail arrivals at inappropriate times disrupt workers engaged in intellectual activities and reduce their productivity. We propose an e-mail delivery mediation system to deal with this issue. The system suspends e-mail delivery and estimates users' interruptibility from their PC operation activities. Then, it delivers e-mail only when the estimated interruptibility matches certain delivery criteria, especially when a user switches applications. A long-term evaluation in a real office revealed that e-mail mediation based on the system's estimates of user interruptibility can shift a certain percentage of the notifications to task or subtask breakpoints or to times at which the user is less engaged in a task.