We develop a framework for studying trade in vertically and horizontally differentiated products. In our model, consumers with heterogeneous incomes and tastes purchase a homogeneous good as well as making a discrete choice of quality and variety of a differentiated product. The distribution of...

We develop a two-country model of endogenous innovation and imitation in order to study the interactions between these two processes. Firms in the North race to bring out the next generation of a set of technology-intensive products. Each product potentially can be improved a countably infinite...

We develop a model of repeated product improvements in a continuum of sectors. Each product follows a stochastic progression up a quality ladder. Progress is not uniform across sectors, so an equilibrium distribution of qualities evolves over time. But the rate of aggregate growth is constant....

Empirical studies have found that enhanced foreign competition can encourage or discourage innovation. To address this relationship, I examine a market structure in which a small number of large multi-product oligopolists compete with a large number of small single-product firms in the same...

Forward-looking investments determine the resilience of firms' supply chains. Such investments confer externalities on other firms in the production network. We compare the equilibrium and optimal allocations in a general equilibrium model with an arbitrary number of vertical production tiers....

This paper considers whether 'liquidity trap' issues have important bearing on the desirability of inflation targeting as a strategy for monetary policy. From a theoretical perspective, it has been suggested that 'expectation trap' and 'indeterminacy' dangers are created by variants of inflation...

The new open-economy macroeconomics' seeks to provide an improved basis for monetary and exchange-rate policy through the construction of open-economy models that feature rational expectations, optimizing agents, and slowly adjusting prices of goods. This paper promotes an alternative approach...

The following arguments are developed: (i) models without monetary aggregates do not imply that inflation is a non-monetary phenomenon and are not necessarily non-monetary models; (ii) theoretical considerations suggest that such models are misspecified, but the quantitative significance of this...

To consider the prospects, looking 20-30 years into the future, for monetary policymaking in accordance with policy rules, one must evaluate their present importance. That requires some definition of what constitutes rule-based monetary policy in practice, since no actual central bank will ever...

This paper reviews the distinction between the timeless perspective and discretionary modes of monetary policymaking, the former representing rule-based policy as recently formalized by Woodford (1999b). In models with forward-looking expectations, this distinction is greater than in the models...