He specializes in contemporary theories of distributive justice, egalitarianism, and justice in health. He is the author of Health, Luck, and Justice (Princeton, 2010), Equality and Opportunity (Oxford, 2013), and Why Inequality Matters (Cambridge, 2016). He has published on justice and equality in a variety of journals such as Utilitas, Economics & Philosophy, Politics, Philosophy, & Economics, Ratio, the Journal of Political Philosophy, the Journal of Applied Philosophy, and the Journal of Moral Philosophy.