Sándor Juhász

selected publications

1. JEG

   Co-location of skill-related suppliers: advancing coagglomeration research using firm-to-firm network data

   Juhász, S., Elekes, Z., Ilyés, V., and Neffke, F.

   Journal of Economic Geography, 2026

   Abs HTML PDF

   Firms in industry clusters benefit from locating close to suppliers and customers. However, the pervasiveness of global value chains questions the need for co-location in buyer–supplier relationships. We propose that supply-chain partners are more likely to co-locate if they exchange not only goods but also know-how, implying superadditivity of Marshallian agglomeration channels. We test this in a coagglomeration framework using microdata for Hungary—a small, open economy deeply embedded in global value chains—examining co-location, labor flows, and value chains between firms and industries. We find that supply chains foster co-location primarily among firms in skill-related industries.

2. RP

   The software complexity of nations

   Juhász, S., Wachs, J., Kaminski, J., and Hidalgo, C. A.

   Research Policy, 2026

   Abs HTML PDF

   Despite the growing importance of the digital sector, research on economic complexity and its implications continues to rely mostly on administrative records—e.g. data on exports, patents, and employment—that have blind spots when it comes to the digital economy. In this paper we use data on the geography of programming languages used in open-source software to extend economic complexity ideas to the digital economy. We estimate a country’s software economic complexity index (ECIsoftware) and show that it complements the ability of measures of complexity based on trade, patents, and research to account for international differences in GDP per capita, income inequality, and emissions. We also show that open-source software follows the principle of relatedness, meaning that a country’s entries and exits in programming languages are partly explained by its current pattern of specialization. Together, these findings help extend economic complexity ideas and their policy implications to the digital economy.

3. PNAS

   Urban highways are barriers to social ties

   Aiello, L. M., Vybornova, A., Juhász, S., Szell, M., and Bokányi, E.

   Proceedings of the National Academy of Sciences, 2025

   Abs HTML PDF

   Urban highways are common, especially in the US, making cities more car-centric. They promise the annihilation of distance but obstruct pedestrian mobility, thus playing a key role in limiting social interactions locally. Although this limiting role is widely acknowledged in urban studies, the quantitative relationship between urban highways and social ties is barely tested. Here we define a Barrier Score that relates massive, geolocated online social network data to highways in the 50 largest US cities. At the unprecedented granularity of individual social ties, we show that urban highways are associated with decreased social connectivity. This barrier effect is especially strong for short distances and consistent with historical cases of highways that were built to purposefully disrupt or isolate Black neighborhoods. By combining spatial infrastructure with social tie data, our method adds a new dimension to demographic studies of social segregation. Our study can inform reparative planning for an evidence-based reduction of spatial inequality, and more generally, support a better integration of the social fabric in urban planning.