An alternative (and probably better) proxy might be child and elderly poverty rates in combination with some measure of economic mobility. These more directly reflect how the social structures of reproduction manifest in public and private preferences and capabilities. But we use the non-income HDI because it proffers a consistent time series for a large number of countries. Countries are categorized into one of three groups according to their 2010 per capita income: low and low middle income, middle income, and high income.7 We split the sample this way because higher-income countries tend to have higher human development, all else equal.