Hope for the Mobility Ratio

Macdonald's criticism of structural models of mobility is empty because it denies ideas or theories a place in model con'struction. Specifically, the equivalent models proposed by Macdonald do not meet the criterion of minimal asymmetry that was applied in the selection of models for British and American mobility tables. Under certain conditions, equivalent models meet the symmetry criterion, but these conditions do not apply to the examples discussed by Macdonald. Also, he exaggerates the usefulness of odds-ratios in formulating models for non-ordered data, and he proposes an empirical revision of the Featheman-Hauser model of mobility to first occupations that is less appealing than the original model. Hope's criticism of the new mobility ratio rests on an illogical comparison between the Featherman-Hauser model and various saturated models of the mobility table. Also, his commenta y makes erroneous statements about the relationship between the FeathermanHauser model and their criticisms of Blau and Duncan and about the relationship between that model and Goodman's quasi-independence models. Macdonald's commentary on structural models of the mobility table is both instructive and cautionary, but I disagree with much of it. I wrote some time ago that "Any number of models may imply the same set of oddsratios, and in this sense they will be equivalent. One such model may be transformed into another by multiplicative rescaling" (b, 453). Macdonald cites this passage as the point of his note, but he questions whether "the force of the known has been attended to." I believe it has, but Macdonald ignores relevant features of my several published analyses of occupational mobility classifications. In this note I will show how Macdonald's criticism *This research was carried out with support from the National Institute for Mental Health (Grant No. 6275) and the National Science Foundation (Grant No. SES-8010640) using computational facilities of the Center for Demography and Ecology at the University of WisconsinMadison, which has core support from the National Institute of Child Health and Human Development (Grant No. 5876). I thank Peter Mossel and Peter Dickinson for assistance in computation. I thank Richard T. Campbell for comments on a draft of this note. I thank John H. Goldthorpe, Robert D. Mare, Michael T. Sobel, Aage 8. Sarensen, and Halliman H. Winsborough for their advice. The opinions expressed herein are those of the author.