The effects of network delays on group work in real-time groupware

Network delays are a fact of life when using real-time groupware over a wide area network such as the Internet. This paper looks at how network delays affect closely-coupled group work in real-time distributed groupware. We first determine the types and amounts of delay that can happen on the Internet, and then identify types of collaborative interactions that are affected by delay. We then examine two interaction types more closely: predicting others' movements, and coordinating shared access to artifacts. We carried out experiments to measure the effects of two kinds of delay (latency and jitter). When these interactions are isolated and repeated, we found that even small delays can lead to significant increases in completion time and errors. Although people in real-world tasks are often able to adapt their actions to accommodate network delays, we conclude that designing groupware to minimise the effects of delay can improve usability for closely-coupled collaboration.