This paper studies the role of social insurance as a redistributive mechanism in the presence of an optimal (linear or general) income tax. It considers a second-best setting with two unobservable individual characteristics: ability, measured by the wage rate, and risk, measured by the...

Atkinson and Stiglitz show that with weakly separability, differential commodity taxes are unnecessary given an optimal nonlinear income tax. Deaton showed that with an optimal linear progressive income tax, commodity taxes are superfluous under weakly separable and linear Engel curves. Using...

This paper studies optimal linear income taxation and redistributive social insurance when the former has the traditional labor distortion and the latter generates both ex ante and ex post moral hazard. Private insurance is available and individuals differ in labor productivity and in loss...