The prospect of capital obsolescence inhibits investment. Investors thus become more optimistic when the obsolescence of their capital slows down. We propose a model with no fixed costs of investment, and random technological progress that induces obsolescence of capital in place. Spikes occur...

New information technology has reduced marginal production and distribution costs of information goods to negligible levels and promises to revolutionize many industries. Unpaid copies of digital products can be as good as paid first-generation copies, and their availability can undermine the...

Recording industry revenue has fallen sharply in the last three years, and some -- but not all -- observers attribute this to file sharing. We collect new data on albums obtained via purchase and downloading, as well as the consumers' valuations of these albums, among a sample of US college...

Machines are more expensive in poor countries, and the relation is pronounced. It is hard for a Solow (1956) type of model to explain the relation between machine prices and GDP given that in most countries equipment investment is under 10% of GDP. A stronger relation emerges in a Solow (1959)...

We present a model of industry evolution where the dynamics are driven by a process of endogenous innovations, followed by subsequent embodiments in physical capital. Traditionally, the only distinction between R&D and physical investment was one of labeling: the first process accumulates an...