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'...

"Recent technological changes may have altered the balance between technology and copyright law for digital products. While file-sharing has reduced revenue, other technological changes have reduced the costs of bringing creative works to market. As a result, we don't know whether the effective...