Beyond Tele-substitution: A Broader Empirical Look at Communication Impacts

Information on the number and types of communication activities (including travel) engaged in over a period of four consecutive days, at two points in time about six months apart, was collected from 91 respondents. A system of structural equations was developed and estimated, expressing the quantity of each type of communication at time 2 as a function of quantities of communication of each type at time 1, the elapsed time between measurements, and exogenous sociodemographic variables. All "own" lagged effects (that is, the effect of one communication type in wave 1 on the same type of communication in wave 2) were found to be positive and (except for information object delivery) highly significant. The "elapsed time" variable was always positive and (except for personal meetings and, in one model, information object delivery) significant; these effects indicate net generation of communication activities over time. Significant "cross" lagged effects (that is, the effect of one communication type in wave 1 on a different type in wave 2) were mostly positive, indicating that the predominant effect across modes is complementarity rather than substitution. Several exogenous variables were also significant in logical ways.