ON THE MEASUREMENT OF SOCIAL MOBILITY AN INDEX OF STATUS PERSISTENCE.

Considering a cross-classification table that describes an aspect of social mobility (the relation between origin status and destination status) for a population of individuals, this paper shows that the usual indices of mobility (or immobility), which are based upon a comparison of the observed frequencies in the mobility table with the corresponding expected frequencies estimated under the assumption of "perfect mobility," are defective in an important respect. A different index is introduced which is not defective in this respect. For those individuals whose origins are in a given status category, the new index measures the degree to which an individual's status of origin "persists" from his origin to his destination. This index can be used to compare the different status categories of origin with respect to their degree of status persistence, and it can also be used for other comparative purposes. Calculating this index of persistence for the data in the classical studies of inter generation social mobility in Britain and in Denmark, we find, for example, that (1) its magnitude is negative for those whose origins are in the middle (M) status category (i.e., there is, in a certain sense, an "exodus" from the middle status category); (2) its magnitude is positive for those whose origins are in the upper (U) or lower (L) status categories; (3) it is greater for those whose origins are in the U status category than for those whose origins are in the L status category; and (4) the magnitudes of the index for the different status categories of origin differ from each other in statistically significant ways. The index of persistence introduced here can serve to supplement and extend some of the methods developed in the author's earlier work. [ABSTRACT FROM AUTHOR]