On the usage patterns of multi-modal communication: Countries and evolution

How do people use phone calls and text messages for their communication needs? Most studies so far study each mode of communication in isolation. Here, we study the interplay of multi-modal communications. We analyze more than a billion call and text records from a Chinese city and San Francisco Area between 2007 and 2011. First, we provide some definitions towards a framework for analyzing multi-modal communications. Then,we study the relationship of the two communication modes and quantify several aspects of correlation and inference. For a communicating pair, we find that the existence of texting during the weekend is the strongest indicator that the pair will communicate at other times with texts or calls. We compare the behavior between China and the U.S. and we find several similarities and differences. For example, we find evidence of an after-lunch siesta among Chinese users. Finally, we study the evolution of the two modes over time. We find that texting has taken over in sheer number of ”events” by flipping the number of calls over that of texts from 2: 1 in 2007 to 1:2 in 2011.