Economic growth amidst staggering inequality in many low- and middle-income countries makes the quest to end global poverty more topical than ever. Calls to leave no one behind in the course of development underscore the need to reconsider the role of policy frameworks in emerging economies. Social policies have been expanded across the Global South during the last decades, and social protection is increasingly highlighted as a fundamental component of the global sustainable development agenda. This thesis, comprising three self-contained studies, analyses the drivers, mechanisms and outcomes of social policy reform in development contexts, asking which economic institutions could enable more rapid advancement towards ending poverty and reducing inequalities, and what conditions promote the expansion of such institutions?

Study I investigates the driving forces of changes in social spending across 46 more recent democracies, with particular attention to the role of partisan politics. Using data from 1995 to 2015, multivariate fixed effect regressions reveal a positive association between left government and public social expenditures, also when controlling for structural and institutional factors. This finding indicates that interests and ideologies, articulated through partisan politics, matter for the evolution of social policy, also in development contexts.

In light of the findings from this quantitative analysis, Study II investigates the mechanisms driving, and hampering, progress towards social policy expansion in a specific case. The politics surrounding a healthcare reform with the ambition to universalise access to public healthcare in Bolivia is examined using theory-guided process tracing methods. The study highlights how policy is shaped through an interaction between societal and state actors as well as how interests and ideas are intertwined in the process, but also how policy legacies give rise to reactive sequences militating against change.

In Study III, the focus is on the outcomes of social policy. The study presents analyses of how government cash transfer systems moderate the effect of economic growth in both absolute and relative child poverty. Longitudinal data from 16 low- and middle-income countries included in the Luxembourg Income Study (LIS) are analysed by means of descriptive statistics and multivariate regression techniques. Findings show that both economic growth and the expansions of transfer schemes are associated with declining absolute poverty. Meanwhile, growth is found to be related to reductions in relative child poverty primarily when combined with sufficiently extensive systems of government transfers, thus pointing to the relevance of social protection for inclusive growth.

The findings from the three studies illustrate that central concepts from comparative welfare state research can be employed also in development contexts, converging on an analytical approach where changes in poverty and inequality are influenced by politics. Continued comparative analyses of social policies and their determinants in development contexts can accordingly generate much-needed insights into the causes of global poverty and inequality. Future research should further explore feedback effects of policy on politics and consider the potential synergies between social policy, equality, and economic growth.