Biases in human estimation of interruptibility

People have developed a variety of conventions for negotiating face to face interruptions. The physical distribution of teams, however, together with the use of computer mediated communication and awareness systems, fundamentally alters what information is available to a person considering an interruption of a remote collaborator. This paper presents a detailed comparison between self-reports of interruptibility, collected from participants over extended periods in their actual work environment, and estimates of this interruptibility, provided by a second set of participants based on audio and video recordings. Our results identify activities and environmental cues that affect participants' ability to correctly estimate interruptibility. We show, for example, that a closed office door had a significant effect on observers' estimation of interruptibility, but did not have an effect on participants' reports of their own interruptibility. We discuss our findings and their importance for successful design of computer-mediated communication and awareness systems.