Jason Wiese, Jun-Ki Min, Jason I. Hong, and John Zimmerman

CMU HCII Technical Report

May 2014

How effective are call and SMS logs in modeling tie strength? Frequency and duration of communication has long been cited as a major aspect of tie strength. Intuitively, this makes sense: people communicate with those that they feel close to. Many highly cited research papers have pushed this idea further, using communication as a direct proxy for tie strength. However, this operationalization has not been validated. Our work evaluates this assumption. We collected call and SMS logs and ground truth relationship data from 40 participants. Consistent with theory, we found that frequent or long-duration communication likely indicates a strong tie. However, little or no communication does not necessarily indicate a weak tie. Follow-up interviews revealed several explanations and indicate fundamental challenges for inferring tie strength from communication logs.