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on Network Economics |
| By: | Wout De Vos (CentER and Department of Econometrics and Operations Research, Tilburg University); Michel Grabisch (Centre d'Economie de la Sorbonne, Université Paris 1 Panthéon-Sorbonne, Paris School of Economics); Agnieszka Rusinowska (Centre d'Economie de la Sorbonne, CNRS, Université Paris 1 Panthéon-Sorbonne, Paris School of Economics) |
| Abstract: | In the present paper, we study opinion dynamics in a social network, where individuals only listen to those with opinion not farther away than a given threshold from their own opinion (known as bounded confidence models, proposed by Hegselmann and Krause). It is well known that in bounded confidence models consensus does not always exist, and that agents split in clusters (polarization), with convergence to consensus in each cluster. We are precisely interested in the effect of bounded confidence on polarization in the network. Our main focus concerns the formation of clusters and their number, as well as its non-monotonicity with respect to the value of the threshold. First, a framework with a finite number of agents is considered. We study analytically disintegration of various types of opinion chains (clusters), and investigate by simulation the likelihood of chains of a certain length and their disintegration. Next, we analyze in a formal way the formation of clusters in a model with a continuum of agents. Finally, we examine the (non-)monotonicity of the number of clusters with respect to the threshold for a given initial vector of opinions and in expectation |
| Keywords: | opinion dynamics; polarization; clusters; bounded confidence; non-monotonicity; network formation; continuous opinion |
| JEL: | D85 D72 |
| Date: | 2025–07 |
| URL: | https://d.repec.org/n?u=RePEc:mse:cesdoc:25018 |
| By: | Charlie Joyez (Université Côte d'Azur, GREDEG, CNRS, France) |
| Abstract: | We study how disruptions propagate through global value chains and how network structure conditions their e ects. Using Eora country-industry data for 189 countries and 26 industries (1996-2015), shocks are defined by a distribution-based rule; exposure counts disrupted upstream/downstream partners, and redundancy counts non-disrupted pre-existing links. We estimate fixed-e ects impact models - where robustness is smaller contemporaneous deterioration conditional on exposure - and a grouped-time complementary log-log hazard - where resilience is faster return to the pre-shock level. Two findings emerge. First, exposure propagates, depressing output, value added, and exports and slowing recovery. Second, redundancy mitigates, offsetting the impact and raising the recovery hazard. As an illustration, high-technology activities appear less sensitive on impact and recover faster than low-technology ones, with the advantage explained by higher redundancy despite deeper connections. These results suggest strengthening robustness and resilience by deepening GVC integration through strategic redundant linkages, rather than retreating from openness. |
| Keywords: | Global Value Chains, Business cycle shocks, High-Technology |
| JEL: | F14 F15 F44 |
| URL: | https://d.repec.org/n?u=RePEc:gre:wpaper:2025-36 |
| By: | Meekes, Jordy (Leiden University); van Lent, Max (Leiden University) |
| Abstract: | Child penalties in paid working hours are persistent and widen the gender earnings gap. This paper studies an important mechanism through which working hours are affected: peer effects. Using three unique layers of peer networks: neighbours, colleagues, and family, we analyse peer effects on individuals’ paid working hours. We analyse peer effects up to six years after childbirth on individuals who become first-time parents in the period 2014-2018, using Dutch full-population administrative monthly microdata up to September 2024. The identification strategy exploits exogenous variation in peers’ working hours through peers-of-peers. Our research is the first to establish long-term statistically significant peer effects on fathers’ working hours. The results indicate positive peer effects on fathers and mothers, where colleague peers are more important than neighbour peers and family peers. |
| Keywords: | peers-of-peers, paid working hours, colleague peers, neighbour peers, family peers |
| JEL: | J22 D85 C26 |
| Date: | 2025–09 |
| URL: | https://d.repec.org/n?u=RePEc:iza:izadps:dp18148 |
| By: | Allaire, Nolwenn; Le Coz, Victor; Benzaquen, Michael; Challe, Damien |
| Abstract: | Using the secured transactions recorded within the Money Markets Statistical Reporting database of the European Central Bank, we test several stylized facts regarding the interbank market of the 47-largest banks in the eurozone. We observe that the surge in the volume of traded evergreen repurchase agreements followed the introduction of the LCR regulation and we measure a rate of collateral re-use consistent with the literature. Regarding the topology of the interbank network, we confirm the high level of network stability but observe a higher density and a higher in– and out–degree symmetry than what is reported for unsecured markets. JEL Classification: E42, E51, E52, G21, G28 |
| Keywords: | collateral re-use, excess liquidity, interbank network, liquidity coverage ratio, monetary policy |
| Date: | 2025–09 |
| URL: | https://d.repec.org/n?u=RePEc:ecb:ecbwps:20253113 |
| By: | Samuel Kortum (Yale University); Bernardo S.C. Ribeiro (Einaudi Institute for Economics and Finance) |
| Abstract: | We explore how connections between buyers and suppliers of intermediate inputs evolve over time to promote firm growth. To formalize this process we develop a dynamic model of a granular endogenous production network, making stark assumptions that yield a tractable parsimonious framework. In the model, producers gradually build up a network of contacts by meeting other producers and source an intermediate input from their cheapest contact at any moment. They retain full recall, so can always switch to a producer contacted previously, even if they never bought from it before. Through this process the production network itself becomes an endogenous state variable in the model that drives firm growth. Despite its simplicity, the implications we derive from this framework are realistic enough to test against numerous findings from the burgeoning empirical literature on firm-to-firm trade. |
| Date: | 2025–09–01 |
| URL: | https://d.repec.org/n?u=RePEc:cwl:cwldpp:2459 |
| By: | De Paola, Maria (University of Calabria); Nistico, Roberto (University of Naples Federico II); Scoppa, Vincenzo (University of Calabria) |
| Abstract: | This paper examines the impact of co-workers’ fertility on individual fertility decisions. Using matched employer-employee data from Italian social security records (2016–2020), we estimate how fertility among co-workers of similar age and occupation affects the individual likelihood of having a child. We exploit variation introduced by the 2015 Jobs Act, which reduced fertility among workers hired under weaker employment protection. Focusing on workers hired before the reform and using the share of colleagues hired after the reform as an instrument for peer fertility, we find that a one-percentage-point increase in peer fertility raises individual fertility by 0.4 percentage points (a 10% increase). Heterogeneity analysis suggests that while social influence and social norms are key mechanisms, information sharing and career concerns, particularly among women, tend to moderate the response. Our findings highlight how changes in employment protection may have unintended fertility spillovers through workplace social interactions. |
| Keywords: | social learning, fertility, EPL, career concerns, social norms, workplace |
| JEL: | C3 J13 J65 J41 M51 |
| Date: | 2025–09 |
| URL: | https://d.repec.org/n?u=RePEc:iza:izadps:dp18127 |
| By: | Dale-Olsen, Harald (Institute for Social Research, Oslo); Finseraas, Henning (Norwegian University of Science and Technology (NTNU)); Nergaard, Kristine (Fafo); Svarstad, Elin (Fafo) |
| Abstract: | Social interactions between young and senior colleagues might have consequences for union membership uptake of young workers, thus influencing public policies on unions. We apply Norwegian administrative register data to test this claim about the influence of social interactions on unionization, while addressing threats of homophily bias, contextual, and network confounding. Leveraging exogenous spillover shocks by colleagues’ siblings’ unionization to colleagues’ unionization, we find causal evidence supporting the notion that social interactions with close colleagues are important for unionization, mainly driven by social costs and information sharing. Our results suggest that one standard deviation increase in the union density of close colleagues, causes the uptake of union membership for young workers to grow by 20-23 percent. Our analyses thus reveal one source of additional spillover impacts from the implementation of public policies supporting unions. Furthermore, our results have important implications for unions’ mobilization strategies. |
| Keywords: | panel data, young workers, social interaction, unionization, IV-analyses |
| JEL: | J50 J51 Z13 |
| Date: | 2025–09 |
| URL: | https://d.repec.org/n?u=RePEc:iza:izadps:dp18139 |
| By: | Ulimwengu, John M. |
| Abstract: | This study develops a dual-framework for identifying points of failure (PFs) and points of entry (PEs) in global food systems. Building on Schneider et al. (2025), we extend their entry-point analysis by introducing PFs—nodes where systemic risk concentrates. Using dynamic systems modeling and directed network analysis of 50 indicators from the Food Systems Countdown Initiative, we derive PF and PE indexes based on structural metrics from the adjacency matrix. While empirically grounded in network topology, the model accommodates behavioral lags and policy sensitivity. Findings reveal that high-risk and high-leverage components often overlap, enabling more strategic and adaptive interventions. Designing interventions without understanding fragility would be akin to engineering a machine for acceleration while ignoring its weakest links. |
| Keywords: | diet; dynamics; food systems; malnutrition; resilience |
| Date: | 2025–09–02 |
| URL: | https://d.repec.org/n?u=RePEc:fpr:ifprid:176309 |
| By: | Hai Yang; Joseph Y. J. Chow |
| Abstract: | Urban mobility is undergoing rapid transformation with the emergence of new services. Mobility hubs (MHs) have been proposed as physical-digital convergence points, offering a range of public and private mobility options in close proximity. By supporting Mobility-as-a-Service, these hubs can serve as focal points where travel decisions intersect with operator strategies. We develop a bilevel MH platform design model that treats MHs as control levers. The upper level (platform) maximizes revenue or flow by setting subsidies to incentivize last-mile operators; the lower level captures joint traveler-operator decisions with a link-based Perturbed Utility Route Choice (PURC) assignment, yielding a strictly convex quadratic program. We reformulate the bilevel problem to a single-level program via the KKT conditions of the lower level and solve it with a gap-penalty method and an iterative warm-start scheme that exploits the computationally cheap lower-level problem. Numerical experiments on a toy network and a Long Island Rail Road (LIRR) case (244 nodes, 469 links, 78 ODs) show that the method attains sub-1% optimality gaps in minutes. In the base LIRR case, the model allows policymakers to quantify the social surplus value of a MH, or the value of enabling subsidy or regulating the microtransit operator's pricing. Comparing link-based subsidies to hub-based subsidies, the latter is computationally more expensive but offers an easier mechanism for comparison and control. |
| Date: | 2025–08 |
| URL: | https://d.repec.org/n?u=RePEc:arx:papers:2509.10465 |