Development debates frequently focus on making economic growth sustainable or ensuring that natural resources are used sustainably
such debates rest on longstanding scholarship and largely shared understandings of how such problems should be addressed. Increasingly, there are also calls for development to be socially sustainable. Yet the theory and evidence undergirding this third "pillar" are comparatively thin, focusing primarily on high-income countries and mapping only partially onto a coherent policy agenda. This paper seeks to help close these gaps by providing (a) a brief history and literature review of social sustainability, emphasizing its distinctiveness from economic and environmental sustainability
(b) a definition and conceptual framework, identifying social sustainability's key components
(c) empirical evidence linking these components to mainstream development outcomes
and (d) operational insights for promoting social sustainability-on its own and as a complement to economic and environmental sustainability. The scale and intensity of the world's current development challenges-and their impacts not just on economies and the environment but entire societies-requires a more robust understanding of their social dimensions, what policies and programs should be enacted in response, and how such efforts can be implemented with local legitimacy and sustained politically over time.