The ranking of a group of distributions can be considered definitive only if it does not vary depending on the index used. The best procedure, therefore, is to use inequality indices in a complementary way and analyse the results jointly. One involves determining to which extent changes in poverty rates are attributable to changes in income level and to which extent they are attributable to changes in income distribution. Another approach evaluates the role of different sources of household income, placing special emphasis on labour market factors that explain changes in labour income. In this section, both methodologies are applied to data from 1990-2008, in order to gain a perspective that complements analyses conducted in previous editions of Social Panorama of Latin America.