I study the cyclical behavior of an equilibrium search model with endogenous job creation and destruction, with focus on the model's failure to match the observed cyclical volatility of unemployment. Job creation in the model is influenced by wages in new matches. I summarize microeconometric...

After some decades of relative oblivion, the interest in the optimality properties of monopolistic competition has recently re-emerged due to the availability of an appropriate and parsimonious framework to deal with firm heterogeneity. Within this framework we show that non-separable utility,...

We estimate a structural model of heterogeneous multiproduct firms to examine the sources of firm heterogeneity emphasized in the recent trade and macro literatures. Using Nielsen barcode data on prices and sales, we estimate elasticities of substitution within and between firms, and use the...

We estimate the effect of consumer search on the price of the purchased product in a physical store environment. We implement the analysis using a unique data set obtained from radio frequency identification tags, which are attached to supermarket shopping carts. This technology allows us to...

There is a growing consensus among economists that extending shop opening hours createsjobs. While this is probably true in deregulating industries, this paper argues there are somedeficiencies in the existing hypotheses about how exactly deregulation affects employment.First, this paper...

A startling fact of firm level productivity analysis is the large and persistent differences in both labour productivity and total factor productivity (TFP) between firms in narrowly defined sectoral classes. The competitiveness of an industry is potentially an important factor explaining this...

This paper develops a model of endogenous product selection by firms. The theory is motivated by new evidence we present on the importance of product switching by U.S. manufacturers. Two-thirds of continuing firms change their product mix every five years, and product switches involve more than...

This paper presents a model of international trade that features heterogeneous firms, relativeendowment differences across countries, and consumer taste for variety. The paper demonstrates thatfirm reactions to trade liberalization generate endogenous Ricardian productivity responses at...

This paper examines the frequency, pervasiveness and determinants of product switching among U.S. manufacturing firms. We find that two-thirds of firms alter their mix of five-digit SIC products every five years, that one-third of the increase in real U.S. manufacturing shipments between 1972...

Studies of firm-level data have shown that there is a huge dispersion of productivity across firms even when industries are narrowly defined. So there is a significant opportunity for the least productive firms to catch up to the most productive. The formers' convergence could therefore...