Determinants of Mobility in Random Exchanges

In this paper, the authors investigate the phenomenon of mobility based on a random exchange model. Economic mobility is a supplemental index in evaluating and comparing inequalities with respect to wealth or income distribution. The dynamic characteristics of mobility can be fully exhibited by an agent-based model in which agents exchange money with each other, and the ranks of individuals always shift over time. It is assumed that agents have propensity to save a part of money when they make exchange. We employ a measurement index which defines mobility as an average variation of rank over a given sampling time interval. The simulation results show that the mobility is not only related with saving rate but also with the sampling time interval. The dependence of mobility on time interval can be accounted for by the autocorrelation analysis of individual ranks.