| Retail chains and the volume of imports of consumer goods from developing countries have grown sharply over the past 25 years. Wal-Mart's sales, which currently account for 15% of U.S. imports of consumer goods from China, grew 90-fold over this period, while U.S. imports from China increased 30-fold. We relate these trends using a model in which scale economies in retail interact with scale economies in the import process. Combined, these scale economies amplify the effects of technological change and trade liberalization, creating a two-way relationship between the chain's size and its sourcing choice. Falling trade barriers increase imports not only through direct reduction of input costs but also through an expanded chain and higher investment in technology. Calculations based on our model suggest that the existence of the chain more than doubles the sensitivity of imports to tariff reductions. Technological innovations account for approximately 60% of Wal-Mart's growth from 1984-2004 and reductions in input cost, due to tariff reductions and changes in sourcing, account for 40% of this growth. [current working paper version] [older working paper version] [Economic Principals post about this paper] |
| We offer a theory for the complementarity between the size of a retail chain and the scope of its business to explain the growth of general-merchandise firms and the expansion of the "superstore" format. The complementarity results from an interaction of the retailer's economies of scale and consumer gains from "one-stop shopping." We find support for our model in micro data from the Census of Retail Trade for 1977-2002. Retail chains with more stores carry more distinct product lines and as retail chains grow they add both stores and product lines. On average, we find that a chain adds one product line, such as shoes, computers, or jewelry, to an existing store with every new store it opens. For the average large chain, adding a new product line throughout the chain is correlated with adding 400 new stores, competing in over 8,000 new markets and increasing its competitive pressure in more than 10,000 additional markets. [working paper version] |
| By exploiting the uneven consolidation in the retail sector over the past few years we find that Chinese and other LDC imports are disproportionately sold by the largest retail firms. Smaller retailers sell almost as many imports but they are more likely to import from high-cost source countries. We apply a numerical algorithm to compute marginal propensities to import by firm size. The largest retail firms' propensity to import from China is 17 percentage points higher than that of smaller retailers; the corresponding difference in import propensities from LDCs as a whole is 27 points. The disproportionate growth of large retailers between 1997 and 2002 explains 5% of the overall growth in consumer goods imports, 20% of the growth in consumer goods imports from China, and 22% of the growth in consumer goods imports from LDCs. [working paper version] |
| This note examines the instrumental variables method used by Neumark, Zhang, and Ciccarella (2005) to analyze Wal-Mart's effect on retail labor markets, and exposes major flaws in that methodology. Neumark, Zhang, and Ciccarella use an interaction between distance from Wal-Mart's headquarters and time effects to predict Wal-Mart's presence in a county, and find that each Wal-Mart store destroys, on average, approximately 200 retail jobs. These findings are in stark contrast to Basker (2005) who found a small, but positive and statistically significant, effect on jobs. I show that the IV estimates obtained by Neumark, Zhang, and Ciccarella confound Wal-Mart's causal effect with other factors. To illustrate the problem, I show that their methodology implies a large impact of Wal-Mart not only on retail employment but also on county manufacturing employment. Reduced-form estimates of the regressions show statistically and economically indistinguishable effects in counties with and without Wal-Mart presence, implying that other factors are most likely driving the results. [working paper version] |
| Job-search and migration behavior differ across educational groups. In this paper, I explore several differences between the migration and search behavior of workers with different levels of education, both theoretically and empirically. I start with two stylized facts. First, the propensity to migrate increases with education. Second, conditional on migration, the probability that a worker moves with a job in hand (rather than moving to search for a job in the new location) also increases with education. I present a simple individual optimization problem that captures these facts and generates a number of predictions about differential sensitivity of migration to observed variables by education. These predictions, including a non-monotonicity of migration elasticities with respect to business-cycle conditions by educational group, and less-educated groups' higher sensitivity to local economic conditions in the migration decision, are verified using CPS data. [working paper version] |