Income Inequality and Population Health: A Global Gradient?

Cross-national empirical research about the link between income inequality and population health produces conflicting conclusions. We address these mixed findings by examining the degree to which the income inequality and health relationship varies with economic development. We estimate fixed-effects models with different measures of income inequality and population health. Results suggest that development moderates the association between inequality and two measures of population health. Our findings produce two generalizations. First, we observe a global gradient in the relationship between income inequality and population health. Second, our results are consistent with income inequality as a proximate or conditional cause of lower population health. Income inequality has a 139.7% to 374.3% more harmful effect on health in poorer than richer countries and a significantly harmful effect in 2.1% to 53.3% of countries in our sample and 6.6% to 67.6% of the world's population but no significantly harmful effect in richer countries.

Explaining the trade-growth link: Assessing diffusion-based and structure-based models of exchange.

International development scholars advance contrasting theoretical explanations for the hypothesized link between trade and growth. Diffusion-based models suggest that trade with integrated partners provides states with greater access to technical knowledge. Structure-based models propose that trading with isolated partners produces a bargaining advantage. In this study, we adjudicate between these competing visions by applying Bonacich's (1987) measure of power centrality to the international trade network. We manipulate the procedure's "attenuation factor" (ß) such that a state's trade centrality can be enhanced when a state is connected to either central or isolated partners. Drawing from a sample of 101 states during the 1980-2000 period, we use difference-of-logs models to assess the impact of trade centrality on economic growth net of controls. We find that the positive relationship between trade centrality and growth peaks when states trade with isolated partners in the periphery.