It Is All in the Family: An Evaluation of Social Class As a Measurement for Family Background Characteristics in Analyses of Sibling Correlations

Sibling correlations have gained increasing interest in inequality studies as a broad measurement of the impact of family background and community influence on individual outcomes. In this paper we analyse how much of this influence that siblings share in their long-run income is due to social class origin. Data is from Statistics Denmark and consists of 151,484 individuals born between 1968 and 1974. The paper is motivated by studies showing that half of the family and community influence on siblings are uncorrelated with traditional intergenerational measures of family background, such as parental income and education. We use variance component analysis to test how different class schemes explain the sibling similarities. The result shows that a modified version of the Erikson-Goldthorpe-Portocarero scheme that accounts for both the emergence of professional classes and the persistence of old classes of self-employed and entrepreneurs has the best fit and accounts for approximately 3 per cent more than parental income and education alone. When parental income, education and social class are included we gain an even better fit as we account for 12 per cent of the sibling similarities in long-run income.