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....

Despite technological advances, an individual car's emissions still cannot be measured reliably enough to impose a Pigovian tax. This paper explores alternative market incentives that could be used instead. We solve for second-best combinations of uniform taxes on gasoline, engine size, and...

This paper presents stochastic simulation results pertaining to the performance of nominal income targeting, here represented as a monetary policy rule that sets quarterly values of an interest rate instrument in response to deviations on existing studies of nominal income growth from a...

This paper explores several issues concerning a possible zero lower bound (ZLB) including its theoretical rationale; the magnitude of effects of low sustained inflation on real interest rates; the validity of analyzing monetary policy in models with no monetary variables; and the dynamic...

This paper argues that, in studying the monetary policy transmission process, more emphasis should be given to the systematic portion of policy behavior and correspondingly less to random shocks basically because shocks account for a very small fraction of policy-instrument variability. Analysis...

We explore the effects of environmental taxes that imprecisely target pollution. A review of actual policies indicates few (if any) examples of a true tax on pollution. More typically, environmental taxes target an input or output that is correlated with pollution. We construct a simple...

A tax on vehicle emissions can efficiently induce all of the cheapest forms of abatement. Consumers could drive less, buy a smaller car with better gas mileage, use cleaner gasoline, and repair pollution control equipment (PCE). However, the technology is not yet available to measure and tax...

We consider a model in which the level of taxes and seignorage are too low to finance government expenditures and debt service. Government debt will therefore grow without bound, implying the eventual need to change policy. Starting with utility maximization, we analyze the effect of the...