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...

Firms selling multiple quality-differentiated products frequently alter their product lines when a competitor enters the market. We present a model of multiproduct monopoly and duopoly using a general `upgrades` approach that yields a powerful analytical framework. We provide a simple...

We present a general Cournot model in which each firm may sell multiple quality-differentiated products. We use an upgrades approach, working not with the actual products, but instead with upgrades from one quality to the next. The properties of single-product Cournot models carry over to the...

Although research and development is widely considered to be an important source of growth, relatively little is known about how its effects differ across industries. This is mainly because much research on the effect of R&D has used either cross-section or time-series data and the remainder has...

Recently, business-university collaborations have become the subject of much interest. It is important to distinguish between `blue-sky` research and more directly commercially applicable research. This paper provides a framework in which to think about the latter. A simple screening model is...