This article traces changes in the descriptions of entrenched social disadvantage, and changes in the way that social description is conceptualised and measured. The article is also an analysis of the importance of categories and categorisation to social policy research; an importance which is recognised relatively rarely. Its focus is on the growing importance of multiplicity as a mode for measuring and conceptualising disadvantage. It argues that multiplicity has become important in social policy, and traces distinct trends in research and policy over the last half-century, and their convergence at particular moments. The rise of multiplicity as a trope for understanding social disadvantage has the effect of rendering social problems as more ‘wicked’ and intractable than they were previously understood to be. The strengths of this are in the sophistication of theoretical, multidisciplinary conceptualisations of disadvantage and the disadvantaged. There may be costs to this, however, in policy responses to addressing people's needs.
