Abstract
In this paper, we aim to clearly explain the complex relation between advancement rate and intergenerational social mobility by formalizing a mathematical model. In order to derive general propositions that do not depend on the particular values of parameters, we simply assume that a society consists of four types of subgroups, namely, the combinations of high/low education and high/low class origin, and that a person with high education is more likely to enter the high class. We analyze two situations-first, the case where class origin has an effect on intergenerational mobility and second, the case where only educational qualifications affect mobility. The former is called the lexicographic order model; the latter, the educational credentialism model. By comparing these two models, we specify the condition that educational expansion leads to the formation of a closed society in terms of intergenerational social mobility. The models also show the relation between the equalization of educational opportunities and a decline in the rate of upward mobility. Moreover, we not only derive theoretical propositions but also attempt to verify the goodness of fit of the models by using nationwide statistical data.
