Recent research has been able to measure two forms of technical change---one (fossil) energy-saving and one saving on capital/labor. The results first show strong evidence for "directed technical change" in the sense that the total resources devoted to saving on the inputs responds endogenously...

The use of competitive search protocols in final goods allows for the specification of models where demand shocks generate propagations that look like productivity shocks. In such environments there is a role for expansion of public expenditures during recessions. We investigate the empirical...

This paper builds a theory of the shape of the distribution of total-factor productiv- ity (TFP) across countries. The data on productivity suggests vast differences across countries, and arguably even has "twin peaks". The theory proposed here is consistent with vast differences in long-run...

We model a labor market with search and matching frictions where some or all workers belong to a (centralized) union, both in the case where coverage is exogenously given and where it is endogenous. Unions are assumed to choose identical wages for all unionized workers, and firms are assumed not...

This paper analyzes a business cycle model with labor market frictions as well as an extensive labor supply margin. There are exogenous aggregate shocks to productivity, the job finding rate, and the separation rate. Workers also face idiosyncratic productivity (wage) shocks that they cannot...

The theory bears some testable predictions. First, the probability of future civil wars increases after each conflict episode. Second, a sequence of "accidental" conflicts can lead to the permanent breakdown of trust, plunging a society into a state of recurrent conflicts (a war trap). This...

We develop a model of the intergenerational transmission of risk preferences and discuss how different types of risk in the economic environment affect risk preferences and entrepreneurship.