Trends in neighborhood-level unemployment in the United States: 1980 to 2000

Although the average rate of unemployment across U.S. metropolitan areas declined between 1980 and 2000, the geographic concentration of the unemployed rose sharply over this period. That is, residential neighborhoods throughout the nation's metropolitan areas became increasingly divided into high- and low-unemployment areas. This paper documents this trend using data on more than 165,000 U.S. Census block groups (neighborhoods) in 361 metropolitan areas over the years 1980, 1990, and 2000; it also examines three potential explanations: (i) urban decentralization, (ii) industrial shifts and declining unionization, and (iii) increasing segregation by income and education. The results offer little support for either of the first two explanations. Rising residential concentration of the unemployed shows little association with changes in population density, industrial composition, or union activity. It does, however, show a significant association with both the degree of segregation according to income as well as education, suggesting that decreases in the extent to which individuals with different levels of income and education live in the same neighborhood may help account for this trend.Unemployment ; Regional economics

Cities, skills, and inequality

The surge in U.S. wage inequality over the past several decades is now commonly attributed to an increase in the returns paid to skill. Although theories differ with respect to why, specifically, this increase has come about, many agree that it is strongly tied to the increase in the relative supply of skilled (i.e. highly educated) workers in the U.S. labor market. A greater supply of skilled labor, for example, may have induced skill-biased technological change or generated greater stratification of workers by skill across firms or jobs. Given that metropolitan areas in the U.S. have long possessed more educated populations than non-metropolitan areas, these theories suggest that the rise in both the returns to skill and wage inequality should have been particularly pronounced in cities. Evidence from the U.S. Census over the period 1950 to 1990 supports both implications.Wages ; Regional economics

Cities and the growth of wages among young workers: evidence from the NLSY

Human capital-based theories of cities suggest that large, economically diverse urban agglomerations increase worker productivity by increasing the rate at which individuals acquire skills. One largely unexplored implication of this theory is that workers in big cities should see faster growth in their earnings over time than comparable workers in smaller markets. This paper examines this implication using data on a sample of young male workers drawn from the National Longitudinal Survey of Youth 1979 Cohort. The results suggest that earnings growth does tend to be faster in large, economically diverse local labor markets - defined as counties and metropolitan areas - than in smaller, more specialized markets. Yet, when examined in greater detail, I also find that this association tends to be the product of faster wage growth due to job changes rather than faster wage growth experienced while on a particular job. This result is consistent with the idea that cities enhance worker productivity through a job search and matching process and, thus, that an important aspect of 'learning' in cities may involve individuals learning about what they do well.Wages ; Labor mobility

Technology and industrial agglomeration: evidence from computer usage

Although the association between industrial agglomeration and productivity has been widely examined and documented, little work has explored the possibility that these `external' productivity shifts are the product of more advanced technologies. This paper offers a look at this hypothesis using data on individual-level computer usage across a sample of U.S. metropolitan areas over the years 1984, 1989, 1993, and 1997. The results indicate that, for a wide array of industries at the two-, three-, and four-digit SIC level, an industry's scale within a metropolitan area is positively associated with the frequency of computer use by its workers. However, in spite of these observable differences in workplace technology, I also find that estimated localization effects on wages are largely not explained by computer usage. Even after controlling for computer use, there remain significant own-industry scale effects in labor earnings.Technology ; Industrial location

Urban decentralization and income inequality: is sprawl associated with rising income segregation across neighborhoods?

Existing research shows an inverse relationship between urban density and the degree of income inequality within metropolitan areas; this information suggests that as urban areas spread out, they become increasingly segregated by income. This paper examines this hypothesis using data covering more than 165,000 block groups within 359 U.S. metropolitan areas for the years 1980, 1990, and 2000. The findings indicate that income inequality-defined by the variance of the log household income distribution-does indeed rise significantly as urban density declines. This increase, however, is associated with rising inequality within block groups as cities spread farther from their central core. The extent of income variation between different block groups, by contrast, shows virtually no association with population density. Accordingly, little evidence supports the notion that urban sprawl is systematically associated with greater residential segregation of households by income.Income distribution ; Income

Industry localization and earnings inequality: evidence from U.S. manufacturing

While the productivity gains associated with the geographic concentration of industry (i.e. localization) are by now well-documented, little work has considered how those gains are distributed across individual workers. This paper offers evidence on the connection between total employment and the relative wage earnings of high- and low-skill workers (i.e. inequality) within two-digit manufacturing industries across the states and a collection of metropolitan areas in the U.S. between 1970 and 1990. Using two different measures - 90-10 percentile gaps in both overall and residual wages - I find that wage dispersion falls substantially as industry employment expands. Results from a simple decomposition of this relationship into average plant-size and plant-count components indicate overwhelmingly that average plant size is the primary driving mechanism. Although not necessarily inconsistent with theories appealing to intermediate inputs or technological spillovers, such findings are particularly supportive of Marshall's (1920) labor market pooling explanation for localization.Wages ; Regional economics

Do localization economies derive from human capital externalities?

One of the most robust findings emerging from studies of industrial agglomeration is the rise in productivity that tends to accompany it. What most studies have not addressed, however, is the potential role played by human capital externalities in driving this relationship. This paper seeks to do so using data from the 1980, 1990, and 2000 US Census covering a collection of 77 (primarily) 3-digit manufacturing industries across a sample of more than 200 metropolitan areas. The analysis generates two primary results. First, a variety of education- and experience-based measures of average human capital rise significantly as an industry's employment in a metropolitan area increases. Hence, clusters of industry do tend to be characterized by larger stocks of human capital. However, second, even after accounting for the level of human capital in a worker's own industry, the overall size of the industry remains strongly associated with wages. Such results suggest that localization economies are largely not the product of knowledge spillovers.Regional economics ; Human capital

Urban decentralization and income inequality: Is sprawl associated with rising income segregation across neighborhoods?

Existing research has found an inverse relationship between urban density and the degree of income inequality within metropolitan areas, suggesting that, as cities spread out, they become increasingly segregated by income. This paper examines this hypothesis using data covering more than 160000 block groups within 359 US metropolitan areas over the years 1980, 1990, and 2000. The findings indicate that income inequality - defined by the variance of the log household income distribution - does indeed rise significantly as urban density declines. This increase, however, is associated with rising inequality within block groups as cities spread out. The extent of income variation exhibited between different block groups, by contrast, shows virtually no association with population density. There is, accordingly, little evidence that sprawl is systematically associated with greater residential segregation of households by income.Income distribution ; Income

Local market scale and the pattern of job changes among young men

In finding a career, workers tend to make numerous job changes, with the majority of 'complex' changes (i.e. those involving changes of industry) occurring relatively early in their working lives. This pattern suggests that workers tend to experiment with different types of work before settling on the one they like best. Of course, since the extent of economic diversity differs substantially across local labor markets in the U.S. (e.g. counties and cities), this career search process may exhibit important differences depending on the size of a worker’s local market. This paper explores this issue using a sample of young male workers drawn from the National Longitudinal Survey of Youth 1979 Cohort. The results uncover two rather striking patterns. First, the likelihood that a worker changes industries rises with the size and diversity of his local labor market when considering the first job change he makes. Second, however, this association gradually decreases as a worker makes greater numbers of job changes. By the time he makes his fourth change, the likelihood of changing industries significantly decreases with the scale and diversity of the local market. Both results are consistent with the idea that cities play an important role in the job matching process.Labor market ; Human capital

Productivity and the geographic concentration of industry: the role of plant scale

A large body of research has established a positive connection between an industry's productivity and the magnitude of its presence within locally defined geographic areas. This paper examines the extent to which this relationship can be explained by a micro-level underpinning commonly associated with productivity: establishment scale. Looking at data on two-digit manufacturing across a sample of U.S. metropolitan areas, I find two primary results. First, average plant size - defined in terms of numbers of workers - increases substantially as an industry's employment in a metropolitan area rises. Second, results from a decomposition of localization effects on labor earnings into plant-size and plant-count components reveal that the widely observed, positive association between a worker's wage and the total employment in his or her own metropolitan area-industry derives predominantly from the former, not the latter. Localization economies, therefore, appear to be the product of plant-level organization rather than pure population effects.Industrial productivity ; Regional economics