THE EFFECTS OF DIFFERENTIAL FERTILITY ON SAMPLING IN STUDIES OF INTERGENERATIONAL SOCIAL MOBILITY

It is held that once soc surveys begin to ask for information about persons related to the randomly sampled person, there is a danger that the data so obtained will not be used to characterize just the random sample but the set of related persons as well. The danger lies in the fact that whereas the R may have been located by valid sampling procedures enabling inferences to be made about the wider pop, the set of related persons may be a sample from whom inferences are liable to be made about pop's they do not represent. Examples are given from studies in the area of intergenerational mobility, specifically, D. V. Glass & Hall's famous table of transition probabilities (D. V. Glass, SOCIAL MOBILITY IN LONDON, Routledge & Kegan Paul, 1954) which is based upon a random sample of adult M's, & D. J. Bartholomew's analysis of that data (STOCHASTIC MODELS FOR SOCIAL PROCESSES, John Wiley & Sons, 1967). The concern expressed here lies in the apparent absence of any recognition of the implications of diff'ial fertility for the sampling procedures employed in mobility studies. E. Weiman.