Tariffs and other policy distortions typically lower real national income relative to what it otherwise would have been for any given rate of factor accumulation. Even while lowering real income, however, policy distortions may raise an economy`s real measured growth rate and so, somewhat...

We develop a tractable dynamic model of productivity growth and technology spillovers that is consistent with the emergence of real world empirical productivity distributions. Firms can improve productivity by engaging in in-house R\&D, or alternatively, by trying to imitate other firms'...