This study explores the role of U.S. ethnic scientific and entrepreneurial communities for international technology transfer to their home countries. U.S. ethnic researchers are quantified through an ethnic-name database and individual patent records. International patent citations confirm knowledge diffuses through ethnic networks, and manufacturing output in foreign countries increases with an elasticity of 0.1–0.3 to stronger scientific integration with the U.S. frontier. Specifications exploiting exogenous changes in U.S. immigration quotas address reverse-causality concerns. Exercises further differentiate responses by development stages in home countries. Ethnic technology transfers are particularly strong in high-tech industries and among Chinese economies.

This study evaluates the impact of high-skilled immigrants on U.S. technology formation. We use reduced-form specifications that exploit large changes in the H-1B visa program. Higher H-1B admissions increase immigrant science and engineering (SE) employment and patenting by inventors with Indian and Chinese names in cities and firms dependent upon the program relative to their peers. Most specifications find limited effects for native SE employment or patenting. We are able to rule out displacement effects, and small crowding-in effects may exist. Total SE employment and invention increases with higher admissions primarily through direct contributions of immigrants.

We examine entrepreneurship and creative destruction following US banking deregulations using US Census Bureau data. US banking reforms brought about exceptional growth in both entrepreneurship and business closures. Most of the closures, however, were the new ventures themselves. Although we find evidence for the standard story of creative destruction, the most pronounced impact was a massive increase in churning among new entrants. We argue that creative destruction requires many business failures along with the few great successes. The successes are difficult to identify ex ante, which is why democratizing entry is an important trait of well-functioning capital markets.

We study the impact of skilled immigrants on the employment structures of US firms using matched employer-employee data. Unlike most previous work, we use the firm as the lens of analysis to account for greater heterogeneity and the fact that many skilled immigrant admissions are driven by firms themselves (e.g., the H-1B visa). OLS and IV specifications show rising overall employment of skilled workers with increased skilled immigrant employment by the firm. Employment expansion is greater for young natives than for their older counterparts. The departure rates for older workers relative to younger workers appear highest for those in STEM occupations.

We model spatial clusters of similar firms. Our model highlights how agglomerative forces lead to localized, individual connections among firms, while interaction costs generate a defined distance over which attraction forces operate. Overlapping firm interactions yield agglomeration clusters that are much larger than the underlying agglomerative forces themselves. Empirically, we demonstrate that our model’s assumptions are present in the structure of technology and labor flows within Silicon Valley. Our model further identifies how the lengths over which agglomerative forces operate influence the shapes and sizes of industrial clusters; we confirm these predictions using variations across patent technology clusters.

Why do firms cluster near one another? We test Marshall's theories of industrial agglomeration by examining which industries locate near one another, or coagglomerate. We construct pairwise coagglomeration indices for US manufacturing industries from the Economic Census. We then relate coagglomeration levels to the degree to which industry pairs share goods, labor, or ideas. To reduce reverse causality, where collocation drives input-output linkages or hiring patterns, we use data from UK industries and from US areas where the two industries are not collocated. All three of Marshall's theories of agglomeration are supported, with input-output linkages particularly important.