A Social Origins Index for Comparative Studies of Social Inequalities

Classic sociological studies on inequality of opportunity and social mobility often rely almost exclusively on social class as a reference for individuals' socioeconomic positions, both at origins and destinations. However, using social class to assess socioeconomic circumstances of origin is not only demanding in terms of data requirements but also insufficient to fully capture socioeconomic background. In this paper, using data from a representative national survey in Mexico, a multidimensional socioeconomic index called the Social Origins Index (SOI) is proposed. The SOI incorporates, in addition to parents' occupational status and education, a sub-index measuring the assets, goods, and services in the household of the family of origin. In addition to outlining the methodology used to construct the SOI, the paper presents evidence showing that levels of inequality of opportunity are significantly higher and social mobility is lower when this index is used, compared to the traditional measure based on social class of origin. The paper concludes with a discussion on the potential of this index as a complementary measure to social class of origin in international comparative analyses assessing inequality of opportunity and the rigidity or fluidity of social stratification regimes.