We present methods for inferring the cost of interrupting users based on multiple streams of events including information generated by interactions with computing devices, visual and acoustical analyses, and data drawn from online calendars. Following a review of prior work on techniques for deliberating about the cost of interruption associated with notifications, we introduce methods for learning models from data that can be used to compute the expected cost of interruption for a user. We describe the Interruption Workbench, a set of event-capture and modeling tools. Finally, we review experiments that characterize the accuracy of the models for predicting interruption cost and discuss research directions. Categories and Subject Descriptors I.2.10, J.4 [Artificial Intelligence, Social and Behavioral Sciences]: Perceptual Analysis, Economics General Terms Human Factors, Economics, Experimentation, Theory Keywords Cognitive models, divided attention, interruption, notifications