Analysis of the Dependency of Call Duration on the Quality of VoIP Calls

This letter analyses call detail records of 16 million live calls over Internet-protocol-based telecommunications networks. The objective is to examine the dependency between average call duration and call quality as perceived by the user. Surprisingly, the analysis suggests that the connection between quality and duration is non-monotonic. This contradicts the common assumption, that higher call quality leads to longer calls. In light of this new finding, the use of average call duration as an indicator for (aggregated) user experience must be reconsidered. The results also impact modeling of user behavior. Based on the finding, such models must account for quality since user behavior is not fully inherent, but also depends on external factors like codec choice and network performance.