existing definitions of social sustainability and propose a pragmatic definition—instead of providing yet another highly complex characterization—that allows us to measure social sustainability across countries. Second, we construct a global database capturing the multiple aspects of social sustainability emphasized by the previous literature. Third, we provide empirical evidence on the relationship between countries’ poverty and income levels and their social sustainability indices. Based on such correlations, we conclude that, as expected, more socially sustainable societies are less likely to be poor—a result that is consistent across choices of social indicators and functional forms and remains the same when evaluating developmental outcomes other than poverty and inequality (such as human capital or human development). Perhaps less expectedly, these associations are not uniform across components of social sustainability, nor across regions worldwide. The evidence ultimately supports the notion that social sustainability matters not only in its own right, but also instrumentally, because it is associated with reduced poverty and increasing income.

This paper is organized as follows. Section 2 reviews the existing literature defining social sustainability and discusses the challenges in arriving at a consensus definition and measurement. Section 3 proposes an alternative, pragmatic approach based on an inclusive and utilitarian definition—away from rigid characterizations—that leads to a global database of social sustainability indicators. Using this database, we can measure each of the social sustainability dimensions we judge to be most meaningful. In section 4, we use those indicators to diagnose how social sustainability is associated with levels of monetary poverty, per capita GDP, and income inequality. Section 5 concludes with several policy implications associated with our key findings.

# **2. Existing definitions of social sustainability: Why is it so difficult to define and measure?**

Social sustainability comprises the multiple social aspects of sustainable development. The concept of sustainable development was defined by the World Commission on Environment and Development (1987:43) as “ _development that meets the needs of the present without compromising the ability of future generations to meet their own needs_ ”. This definition questions whether natural resources can be infinitely substitutable, that is, whether technology can ensure the infinite exploitation of natural resources. Sustainability rests on the premise that the circumstances of those who are in need can and must be improved without further degradation of the ecosystem (ICA 2016). Over time, social aspects started to appear alongside the dominant environment-economy tension embedded in the original definition of sustainability (Giddings, Hopwood and O’Brien 2002, Rasouli and Kumarasuriyar 2016). The definition in the 1992 Earth Summit Agenda 21 implicitly mentioned human development and the social dimensions of sustainability. These were included, however, only in a subordinate role, as a contributor to the preservation of the environment. Since then, social sustainability has continued to gain weight in the sustainability debate (Turkington and Sangster 2006), prompting a growing realization that neither social, environmental, nor economic sustainability can be considered in isolation but only in relational terms (Becker et al 1999, World Bank 2013, Purvis, Mao and Robinson 2019). As part of this process, themes included in social sustainability discussions like basic needs, poverty reduction, human development, livelihoods, and equity have been recently and increasingly complemented by themes of identity, sense of place, and the stability and 3