Changes in product characteristics on the extensive margin are an important and hitherto neglected dimension of quality change. Standard techniques for quality-adjusting price indices cannot handle such changes satisfactorily, which leads to an economically and statistically significant bias in...

This paper presents a new model of oligopoly in general equilibrium and explores its implications for positive and normative aspects of international trade. Assuming "continuum-Pollak" preferences, the model allows for consistent aggregation over a continuum of sectors, in each of which a small...

We compare trade liberalization under Cournot and Bertrand competition in reciprocal markets. In both cases, the critical level of trade costs below which the possibility of trade affects the domestic firm’s behavior is the same; trade liberalization increases trade volume monotonically; and...

We provide an overview and synthesis of recent work on models of monopolistic competition with heterogeneous firms in international trade, paying particular attention to competition effects, pass-through, selection effects, and linking distributions of firm characteristics and outcomes. A...

We derive exact conditions relating the distributions of firm productivity, sales, output, and markups to the form of demand in monopolistic competition. Applications include a new “CREMR” demand function (Constant Revenue Elasticity of Marginal Revenue): it is necessary and sufficient for...

Gravity as both fact and theory is one of the great success stories of recent research on international trade, and has featured prominently in the policy debate over Brexit. We first review the facts, noting the overwhelming evidence that trade tends to fall with distance. We then introduce some...