We derive testable conditions ensuring that the income tax is optimal when agents are ex-ante identical but face idiosyncratic income risk. The optimal tax depends positively on both absolute risk aversion and risk variance and negatively on labor supply elasticity and absolute prudence. The...

We derive testable conditions ensuring that the income tax is optimal when agents are ex-ante identical but face idiosyncratic income risk. The optimal tax depends positively on both absolute risk aversion and risk variance and negatively on labor supply elasticity and absolute prudence. The...