We propose a framework for analyzing transformations of demand. Such transformations frequently stem from changes in the dispersion of consumers` valuations, which lead to rotations of the demand curve. In a wide variety of settings, profits are a U-shaped function of dispersion. A high level of...

What is the impact of modern transportation technology on long-run economic change in poor countries with high trade costs?  Rail construction in colonial Sub-Saharan Africa provides a natural experiment: 90% of African rail-road lines were built before independence, in a context where...