Key points are not available for this paper at this time.
A version of this paper was read at the 1978 meetings of the International Sociological Association in Uppsala, Sweden. The Research Foundation of the City University of New York provided funds for the research. The authors acknowledge suggestions made by John Hammond and especially want to thank Hilary Silver for her help with the computer analysis. We are indebted to the ASQ reviewers, whose detailed criticisms on earlier drafts were extremely valuable.
Blau et al. (Fri,) studied this question.