George Mason University Professor Tyler Cowen wrote in the Marginal Revolution blog that "his main contribution is a better understanding of the Phillips curve and the dynamics of short-run unemployment and the concept of the natural rate of unemployment." Cowen also wrote that "his 1960s macro work was true, important, and extremely influential. The capital theory work endures and provides a foundation for subsequent theory. The overall scope is impressive, and Phelps's concerns never strayed far from the real world." Cowen by writing that the award to Phelps meant: "The big questions still matter. Unemployment, economic growth, labor markets, capital accumulation, fairness, discrimination, and justice across the generations are indeed worthy of economic attention."