Intergenerational Mobility: Core Model of Social Fluidity

Abstract

The analysis of intergenerational social mobility is usually carried out using log‐linear or log‐multiplicative statistical models applied to a contingency table which cross‐classifies individuals’ current class (usually called “class destination”) with the class in which they were brought up (“class origin”). An important distinction is between absolute and relative mobility (sometimes called “social fluidity”). Absolute mobility refers to the distribution of cases in the mobility table. Social fluidity refers to the inequality between individuals from different classes in their chances of coming to occupy one rather than another destination class. It is captured by odds ratios which are measured as the proportion of cases that originate in class A and are found in destination class X rather than class Y, divided by the proportion of cases from origin class B which are found in destination X rather than Y. An odds ratio of one indicates that the chances of being in destination class X rather than in Y are the same for those originating in both A and B, while an odds ratio greater than one shows that those born in A are more likely than those born in B to be in X rather than Y, and conversely for an odds ratio less than one. An important feature of odds ratios is that they are unaffected by any scalar multiplication of one or more rows and/or columns of a table: thus, inequalities in access to particular class destinations can be compared across mobility tables, despite the fact that they differ in their distributions of origins and destinations.