We view sustainability as a requirement that welfare should not be expected to decline over time. We impose this requirement as a prior constraint on the consumption-savings-investment problem, and study its implications for saving, risky investment, and the social discount rate. The constraint...

How does the sustainable level of consumption depend on productivity growth and the size and growth rate of the population? What is the effect of uncertainty over these growth rates? I address these questions using a model in which productivity and population growth are stochastic, and social...

Over the past decade, non-Paris Club creditors, notably China, have become an important source of financing for low- and middle-income countries. In contrast with typical sovereign debt, these lending arrangements are not public, and other creditors have no information about their magnitude. We...