Where does adaptation to innovation take place? I present evidence on the role of agglomeration economies in the application of new knowledge to production. All else equal, workers are more likely to be observed in new work in locations initially dense in college graduates and industry variety. This pattern is consistent with economies from the geographic concentration of factors and markets related to technological adaptation. A main contribution is a new measure, based on revisions to occupation classifications, that characterizes cross-sectional differences across cities in technological adaptation. Worker-level results also provide new evidence on the skill bias of recent innovations.

Abstract Why do freeways affect spatial structure? We identify and quantify the local disamenity effects of freeways. Freeways cause slower growth in central neighborhoods (where local disamenities exceed regional accessibility benefits) compared with outlying neighborhoods (where access benefits exceed disamenities). A quantitative model calibrated to Chicago attributes one-third of the effect of freeways on central-city decline to reduced quality of life. Barrier effects are a major factor in the disamenity value of a freeway. Local disamenities from freeways, as opposed to their regional accessibility benefits, had large effects on the spatial structure of cities, suburbanization, and welfare.

We present theory and evidence highlighting the role of natural amenities in neighbourhood dynamics, suburbanization, and variation across cities in the persistence of the spatial distribution of income. Our model generates three predictions that we confirm using a novel database of consistent-boundary neighbourhoods in U.S. metropolitan areas, 1880–2010, and spatial data for natural features such as coastlines and hills. First, persistent natural amenities anchor neighbourhoods to high incomes over time. Secondly, naturally heterogeneous cities exhibit persistent spatial distributions of income. Thirdly, downtown neighbourhoods in coastal cities were less susceptible to the widespread decentralization of income in the mid-twentieth century and experienced an increase in income more quickly after 1980.

Many cities in North America formed at obstacles to water navigation, where continued transport required overland hauling or portage . Portage sites attracted commerce and supporting services, and places where the falls provided water power attracted manufacturing during early industrialization. We examine portage sites in the U.S. South, Mid-Atlantic, and Midwest, including those on the fall line , a geomorphological feature in the southeastern United States marking the final rapids on rivers before the ocean. Although their original advantages have long since become obsolete, we document the continuing importance of historical portage sites. We interpret these results as path dependence and contrast explanations based on sunk costs interacting with decreasing versus increasing returns to scale.

We contrast evidence of urban path dependence with efforts to analyze calibrated models of city sizes. Recent evidence of persistent city sizes following the obsolescence of historical advantages suggests that path dependence cannot be understood as the medium-run effect of legacy capital but instead as the long-run effect of equilibrium selection. In contrast, a different, recent literature uses stylized models in which fundamentals uniquely determine city size. We show that a commonly used model is inconsistent with evidence of long run persistence in city sizes and propose several modifications that might allow for multiplicity and thus historical path dependence.

ABSTRACT Focusing on mandatory partner rotations, we examine the importance of within‐firm network connections to the selection of successor partners and the impact of those connections on post‐rotation audit performance. Using data from China, we track partners' history and identify incumbent‐successor connections stemming from jointly conducted prior engagements. Although these connections can enhance incumbent‐successor information transfers and thus post‐rotation audit performance, they may also pose a threat to quality by compromising the successor's independence. Among the pool of replacement candidates, we find that individuals with stronger connections with the incumbent are more likely to be appointed as successors. This finding is more pronounced when the audit engagement is more complex, client‐specific knowledge is not readily available to the succeeding partner, and the engagement is more valuable to the audit firm. We also document that successor‐incumbent connections are associated with equal or better post‐rotation audit quality and fewer client defections. These results suggest that the benefits of network‐based successor selection may outweigh its costs. By enriching our understanding of the partner transition process, this study contributes to the public policy discourse on partner rotation.

Abstract Does social distancing harm innovation? We estimate the effect of nonpharmaceutical interventions (NPIs)—policies that restrict interactions in an attempt to slow the spread of disease—on local invention. We construct a panel of issued patents and NPIs adopted by 50 large U.S. cities during the 1918 flu pandemic. Difference-in-differences estimates show that cities adopting longer NPIs did not experience a decline in patenting during the pandemic relative to short-NPI cities, and they recorded higher patenting afterward. Rather than reduce local invention by restricting localized knowledge spillovers, NPIs adopted during the pandemic may have preserved other inventive factors.