"This paper compares the structural approach to economic policy analysis with the program evaluation approach. It offers a third way to do policy analysis that combines the best features of both approaches. We illustrate the value of this alternative approach by making the implicit economics of...

This paper surveys some of the strategic aspects that emerge if players fight in an alliance against an enemy. The survey includes the free-rider problem and the hold-up problem that emerges in the baseline model, the role of supermodularity in alliance members' effort contributions, the role of...

This paper distills and extends recent research on the economics of human development and social mobility. It summarizes the evidence from diverse literatures on the importance of early life conditions in shaping multiple life skills and the evidence on critical and sensitive investment periods...