title: Sibship size and educational attainment. A joint test of the Confluence Model and the Resource Dilution Hypothesis.
abstract: Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories - for substantively different reasons - predict that sibship size should have a negative effect on educational attainment most studies cannot distinguish empirically between the CM and the RDH. In this paper, I use the different theoretical predictions in the CM and RDH on the role of cognitive ability as a partial or complete mediator of the effect of sibship size to distinguish the two theories and to identify a unique RDH effect on educational attainment. Using sibling data from the Wisconsin Longitudinal Study (WLS) and a random effect Instrumental Variable model I find that, in addition to a negative effect on cognitive ability, sibship size also has a strong negative effect on educational attainment which is uniquely explained by the RDH.
authors.affiliation: The Danish National Centre for Social Research, Research Group on Social Policy and Welfare Services, Herluf Trolles Gade 11, DK-1052 Copenhagen K., Denmark.
authors.forename: Mads Meier
authors.initials: MM
authors.lastname: Jæger