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on Economic Geography |
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Issue of 2026–04–06
five papers chosen by Andreas Koch, Institut für Angewandte Wirtschaftsforschung |
| By: | Leyan Wu; Yong Huang; Wei Lu; Akrati Saxena; Vincent Traag |
| Abstract: | Scientific knowledge flows enable cumulative progress by connecting researchers across disciplines, institutions, and countries. Yet it remains unclear how geography and national structures continue to shape these exchanges in an increasingly connected world. Using a large-scale bibliometric dataset from OpenAlex, which covers 39.35 million publications across 95 countries and 3, 794 cities between 2000 and 2022, we examine global knowledge diffusion through two complementary channels: co-authorship and citation. We find that the constraining effect of geographic distance on collaboration has not diminished over time but has instead intensified, suggesting persistent structural or institutional barriers. Citation flows, by contrast, are less sensitive to spatial proximity, indicating that intellectual influence may diffuse more freely across borders. At the country level, research networks exhibit strong domestic preferences and a shared citation orientation toward the United States. China, while increasingly favored as a collaboration partner by other countries, continues to be systematically undercited within global citation flows. International mobility increases researchers' collaboration with scholars in their host country but has limited effects on citation flows. These results highlight the structural persistence of spatial and country biases in global science, with implications for equitable participation and recognition across regions. |
| Date: | 2026–04 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2604.01602 |
| By: | Wiebe, Michael |
| Abstract: | Moretti (2021a, b) (henceforth M21) studies agglomeration effects for innovation, testing whether the size of technology clusters causes patenting. Agglomeration effects are important for understanding technological progress (Kerr and Robert-Nicoud, 2020), and are affected by constraints on housing supply (Duranton and Puga, 2020). Using US data on patents filed between 1971 and 2007 (Zucker and Darby, 2014), M21 presents multiple lines of evidence supporting a causal effect of cluster size on patenting. The baseline results are from linear regressions of patents on cluster size, controlling for an extensive set of fixed effects (including inventor effects). The main finding is an elasticity of patenting with respect to cluster size of 0.0676. In this comment, I identify two major problems in M21. First, M21 uses an event study to test for selection bias from promising inventors sorting into large clusters. The event is inventors moving across cities, but M21's specification does not use the variation in cluster size generated by moving. I construct an event study following the literature on 'mover' designs, where the change in average cluster size is interacted with event time indicators. I find a null effect, which is consistent with no causal effect of cluster size, but could also be explained by attenuation bias from moves being misclassified in the data. Second, M21 uses an instrumental variables strategy to control for omitted variable bias from sources like local field-specific subsidies. The instrument is based on changes in the number of inventors in other cities. Due to a coding error, the data is not sorted by city, so the instrument is constructed incorrectly by taking first-differences across cities. When I calculate the first-difference within cities, the estimates are nonsignificant. |
| Date: | 2026 |
| URL: | https://d.repec.org/n?u=RePEc:zbw:i4rdps:292 |
| By: | Shota Fujishima |
| Abstract: | This paper examines the latent functional block structure of Japan's production network using interregional input-output data. To isolate non-trivial production linkages, we first estimate a structural gravity model to account for spatial frictions and economic scale, and then apply a weighted stochastic blockmodel (SBM) to the resulting residual network. Because these residual linkages often connect distant regions, the SBM is well suited to grouping region-industry pairs based on their shared macroeconomic roles. The results reveal that even after explicitly filtering out the mechanical effects of geographic proximity, the network is organized into functional blocks that maintain a high degree of regional coherence. Beyond this baseline spatial clustering, we find evidence of cross-regional integration, a structural bifurcation between manufacturing and urban services in metropolitan areas, and broadly spanning primary sectors. These findings provide a network-based perspective on regional coordination, offering guidance for how structurally defined production blocks-rather than simple geographic proximity-can inform wide-area policy design. |
| Date: | 2026–03 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2603.25300 |
| By: | Bergantino, Angela Stefania; Caravaggio, Nicola; Intini, Mario; Resce, Giuliano |
| Abstract: | This study evaluates whether the Italian National Strategy for Inner Areas (SNAI) has improved accessibility to essential services in peripheral municipalities. Introduced in 2014, the SNAI targets territories characterized by demographic decline and limited access to key services such as schools, healthcare, and transport infrastructure. Using real-time travel data from OpenStreetMap (OSM) and Tom Tom, we develop a replicable framework to monitor driving times to service hubs for more than 7, 600 Italian municipalities. Our tool replicates the methodology used to identify Inner Areas during the second programming cycle of the SNAI (2021-2027). Applying this framework, we update the classification of Inner Areas for 2025 and document a 20% increase in their number compared with the latest official classification. We then estimate a two-period Difference-in-Differences (DiD) model combined with Propensity Score Matching (PSM) to compare municipalities targeted by the strategy with similar non-targeted areas. The results suggest that municipalities included in the SNAI did not experience improvements in accessibility during the period considered. On average, treated municipalities display a modest increase in travel times of about 2.4 minutes relative to comparable Inner Areas not included in the strategy. These findings indicate that, while the SNAI may contribute to broader territorial development objectives, measurable improvements in road accessibility remain limited. |
| Keywords: | place-based policy, inner areas, policy evaluation, Italy |
| JEL: | C31 O18 R58 |
| Date: | 2026–03–23 |
| URL: | https://d.repec.org/n?u=RePEc:mol:ecsdps:esdp26103 |
| By: | Alaina Barca; Evan Mast |
| Abstract: | We construct a new neighborhood geography using a revealed preference intuition: If people disproportionately move within neighborhoods, their boundaries can be backed out from migration flows. Our “districts, ” which consist of about nine census tracts each, correspond to recognizable local areas, as their boundaries align with physical barriers, sharp demographic changes, and local government borders. To illustrate applications, we first show that tract-level analyses of neighborhood sorting miss important broader patterns. Second, aggregating tract-level intergenerational mobility estimates to the district level increases precision threefold while introducing little aggregation bias, resulting in improved predictive power in a hold-out sample. |
| Keywords: | Neighborhood definition; residential mobility; residential sorting |
| JEL: | R23 |
| Date: | 2026–03–24 |
| URL: | https://d.repec.org/n?u=RePEc:fip:fedpwp:102934 |