We study optimal tax policies in a life-cycle economy with risky human capital and permanent ability differences. The optimal policies balance redistribution across agents, insurance against human capital shocks, and incentives to learn and work. In the optimum, i) if utility is separable in...

We study efficient allocations and optimal policies in a life-cycle economy with risky human capital accumulation. The agents are ex-ante heterogeneous in their initial human capital and in their ability level. Ex-post, they also differ in their realization of shocks to human capital. The model...

The Nelder-Mead simplex method is an optimization routine that works well with irregular objective functions. For a function of n parameters, it compares the objective function at the n 1 vertices of a simplex and updates the worst vertex through simplex search steps. However, a standard serial...

The US economy has undergone a number of puzzling changes in recent decades. Large firms now account for a greater share of economic activity, new firms are being created at a slower rate, and workers are getting paid a smaller share of GDP. This paper shows that changes in population growth...