The research The Social Dimensions of Inequality (PDSD) is a unique initiative within the Brazilian social sciences. The research stems from the Project for Stratification and Social Mobility Indicators, coordinated by the researcher Nelson do Valle Silva (IESP-UERJ), with CNPQ funding, and who conducted fieldwork throughout Brazil producing a (random) sample with national representation and with a design comparable to the current National Research Sampling (PNAD-IBGE) until 2004 (i.e. only the rural areas of the North have not been researched).