Abstract - I study the role of social networks in the propagation of economic shocks across space. Combining comprehensive data on US online friendships with extraction activity during the fracking boom, I show that exogenous changes in economic conditions in one area affect outcomes in socially proximate places, regardless of how far apart they are geographically. Social exposure to fracking generates a wage spillover amounting to one-third of every dollar of energy produced in a county’s social network. This spillover decays slowly in space and is associated with a large mobility response. Diffusion mainly stems from the commuting of transient fracking workers.

Abstract - What happens to local communities when manufacturing disappears? I examine changes in associational density over nearly two decades as a proxy for social capital in US labour markets. Exploiting plausibly exogenous trade-induced shocks to local manufacturing activity, I test whether deindustrialisation is associated with greater or lower organisational membership. I uncover a robust negative relationship between the two variables, particularly acute in rural and mostly-White areas. My findings, however, are sensitive to measurement: there are no clearly discernible effects of deindustrialisation on social capital when I consider alternative proxies for the outcome. To reconcile these results, I present evidence suggesting that economic adversity may induce a qualitative, rather than quantitative, change in social capital.

Abstract - Do students benefit differently from interacting with similar and diverse peers? Using register-linked survey data from a stratified sample of Swedish classrooms I test whether endogenous peer effects in student achievement are heterogeneous by immigrant status. My empirical strategy combines instrumental variables, classroom fixed effects, and a control function to identify the parameter of interest separately from contextual and correlated effects. In particular, by considering partially overlapping networks of peers and family members, I use peers' parents' education as instruments for peer behaviour. My findings suggest that endogenous effects are limited to interactions with native peers only, but benefit both native and migrant students. High-ability children of migrants appear to be particularly vulnerable to friendship segregation.

Abstract - The concept of regional development trap refers to regions that face significant structural challenges in retrieving past dynamism or improving prosperity for their residents. This article introduces and measures the concept of the regional development trap for regions in Europe. The concept draws inspiration from the middle-income trap in international development theory but widens it to shed light on traps in higher-income countries and at the regional scale. We propose indicators—involving the economic, productivity, and employment performance of regions relative to themselves in the immediate past, and to other regions in their respective countries and elsewhere in Europe—to identify regions either in a development trap or at significant near-term risk of falling into it. Regions facing development traps generate economic, social, and political risks at the national scale but also for Europe as a whole.

Abstract - The mining of several critical raw materials – including the so-called 'conflict minerals' associated with armed conflict and human rights abuses – and their combination, refining and use in many new advanced electronic products, are providing an important material infrastructure to current technological progress. Relying on text analysis of USPTO patent data between 1976 and 2017, our explorative study provides a methodological and empirical starting point for exploring the technological and geographical linkages between technological paradigms and selected critical and conflict materials (CCMs). Our descriptive analysis finds evidence of a clear association between ICT technologies and CCM intensity over time, and of a striking resource-technology divide in global ICT value chains between value creating and value extracting activities across Global North and Global South and their regions. The paper intends to emphasize the need for a more critical, spatially sensitive approach to studying resource-based technological change to expose the uneven development consequences created, sustained, or mitigated by technological progress.

Abstract - Do informal social ties connecting inventors across distant places promote knowledge flows between them? To measure informal ties, we use a new and direct index of social connectedness of regions based on aggregate Facebook friendships. We use a well-established identification strategy that relies on matching inventor citations with citations from examiners. Moreover, we isolate the specific effect of informal connections, above and beyond formal professional ties (co-inventor networks) and geographic proximity. We identify a significant and robust effect of informal ties on patent citations. Further, we find that the effect of geographic proximity on knowledge flows is entirely explained by informal social ties and professional networks. We also show that the effect of informal social ties on knowledge flows is greater for new entrepreneurs or ‘garage inventors’, for older or ‘forgotten’ patents, and for flows across distant technology fields. It has also become increasingly important over the last two decades.

Abstract - In analogy to the controversial ‘acting White’ narrative for racial achievement gaps among US children, I explore whether migrant background pupils in Europe are exposed to similar social pressure by their peers not to adopt behaviours perceived to be typical of the majority group, notably doing well in school. Leveraging comprehensive longitudinal data on classroom interactions and several proxies for academic achievement, including predetermined measures of ability, I show that there is little evidence in support of this ‘acting native’ hypothesis in the European context.

Abstract - We study the extent of segregation in the social space of urban America. We measure segregation as the (lack of) actual personal connections between groups as opposed to conventional measures based on own neighbourhood composition. We distinguish social segregation from geographical definitions of segregation, and build and compare city-level indices of each. Conditional on residential segregation, cities with more institutions that foster social cohesion (churches and community associations) are less socially segregated. Looking at within-city variation across neighbourhoods, growing up more socially exposed to non-white neighbourhoods is related to various adulthood outcomes (jailed, income rank, married, and non-migrant) for black individuals. Social exposure to non-white neighbourhoods is always related to worsening adulthood outcomes in neighbourhoods that are majority non-white. Our results suggest that social connections, beyond residential location or other spatial relationships, are important for understanding the effective segregation of race in America.