Symmetry and hierarchy in social mobility: a methodological analysis of the CASMIN model of class mobility

The CASMIN model of class mobility proposed by Erikson and Goldthorpe advances our understanding of cross-national differences in social mobility in a number of important ways, most notably by showing how differences in the association between social origins and destinations reflect consequences of public policies that enhance or restrict opportunities. We respecify the CASMIN model in ways that clarify (a) the role of socio-economic differences among classes in mobility processes and (b) the extent of cross-national variation. In particular, the problems with the CASMIN model are its application to highly aggregated occupational classes, its suppression of hierarchical or vertical differences among classes, and its asymmetric classification of origin and destination classes. Our alternative specification is based on greater occupational detail, incorporates continuous covariates in linear-by-linear expressions that are analogous to regression models, and imposes symmetry on the association between origins and destinations. We find that the CASMIN model understates the importance of hierarchy relative to sector and inheritance in the determination of mobility patterns generally as well as in cross-national differences. Furthermore, the symmetry of our model facilitates the analysis of structural mobility as a factor that contributes to cross-national differences in overall mobility rates.