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on Network Economics |
| By: | William C. Horrace (Center for Policy Research, Maxwell School, Syracuse University, 426 Eggers Hall, Syracuse, NY 13244); Hyunseok Jung (University of Arkansas); Jonathan L. Pressler (Saint Louis University); Amy Ellen Schwartz (Center for Policy Research, Maxwell School, Syracuse University, 426 Eggers Hall, Syracuse, NY 13244) |
| Abstract: | We identify and estimate the effects of student-level social spillovers on standardized test performance in New York City (NYC) elementary schools. We leverage student demographic data to construct within classroom social networks based on shared student characteristics, such as a gender or ethnicity. Rather than aggregate shared characteristics into a single network matrix, we specify additively separate network matrices for each shared characteristic and estimate city-wide peer effects for each one. Conditional on sharing a classroom, we find that the most important student peer effects are shared ethnicity, gender, and primary language spoken at home. Identification of the model is discussed. |
| Keywords: | Peer Effect, Network, Homophily, Education |
| JEL: | C31 I21 |
| Date: | 2021–11 |
| URL: | http://d.repec.org/n?u=RePEc:max:cprwps:241&r= |
| By: | Matthew Elliott (CAM - University of Cambridge [UK]); Benjamin Golub (Northwestern University [Evanston]); Matthew Leduc (PSE - Paris School of Economics - ENPC - École des Ponts ParisTech - ENS Paris - École normale supérieure - Paris - PSL - Université Paris sciences et lettres - UP1 - Université Paris 1 Panthéon-Sorbonne - CNRS - Centre National de la Recherche Scientifique - EHESS - École des hautes études en sciences sociales - INRAE - Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, PJSE - Paris Jourdan Sciences Economiques - UP1 - Université Paris 1 Panthéon-Sorbonne - ENS Paris - École normale supérieure - Paris - PSL - Université Paris sciences et lettres - EHESS - École des hautes études en sciences sociales - ENPC - École des Ponts ParisTech - CNRS - Centre National de la Recherche Scientifique - INRAE - Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement) |
| Abstract: | We model the production of complex goods in a large supply network. Each firm sources several essential inputs through relationships with other firms. Individual supply relationships are at risk of idiosyncratic failure, which threatens to disrupt production. To protect against this, firms multisource inputs and strategically invest to make relationships stronger, trading off the cost of investment against the benefits of increased robustness. We find that equilibrium aggregate production is robust to idiosyncratic disruptions. Nevertheless, there is a regime in which arbitrarily small systemic shocks cause arbitrarily steep drops in output, so that the the supply network is fragile. The endogenous configuration of supply networks provides a new channel for the powerful amplification of shocks. |
| Date: | 2021–09–30 |
| URL: | http://d.repec.org/n?u=RePEc:hal:wpaper:halshs-03359607&r= |
| By: | Michel Alexandre; Thiago Christiano Silva; Krzysztof Michalak; Francisco A. Rodrigues |
| Abstract: | In network models of systemic risk, the loss distribution of a distressed debtor among its creditors follows a pro-rata fashion. It is proportional to the loan granted to the debtor. Despite its simplicity, this assumption is unrealistic. In this study, we create a framework for the computation of the systemic risk assuming a heterogeneous pattern of loss distribution, the default pecking order. Distressed debtors employ some criterion (equity, out-degree, or loan extended) to rank the creditors they are willing to default on first. Applying this framework to an extensive Brazilian data set, we found out the adoption of the default pecking order increases significantly the systemic risk. The rise in the systemic risk brought by the heterogeneous distribution over the homogeneous case decreases with the level of the initial shock and is higher for small-sized agents. This result can be interpreted in the light of the dual role of the financial network, which can be a channel for both risk-sharing and shock propagation. We test this hypothesis by assessing the role of interconnectedness (as measured by the network density) in driving the systemic risk. The results corroborate this hypothesis. When the homogeneous loss distribution (which maximizes risk-sharing) is abandoned, the density has a positive impact on the systemic risk. It suggests in this case the financial network acts mainly as a channel for shock propagation rather than for risk-sharing. |
| Date: | 2021–10 |
| URL: | http://d.repec.org/n?u=RePEc:bcb:wpaper:557&r= |
| By: | Clément Bosquet (SERC - Spatial Economic Research Center - LSE - London School of Economics and Political Science); Pierre-Philippe Combes (GREQAM - Groupement de Recherche en Économie Quantitative d'Aix-Marseille - ECM - École Centrale de Marseille - CNRS - Centre National de la Recherche Scientifique - AMU - Aix Marseille Université - EHESS - École des hautes études en sciences sociales, ECON - Département d'économie (Sciences Po) - Sciences Po - Sciences Po - CNRS - Centre National de la Recherche Scientifique, CEPR - Center for Economic Policy Research - CEPR); Emeric Henry (ECON - Département d'économie (Sciences Po) - Sciences Po - Sciences Po - CNRS - Centre National de la Recherche Scientifique, CEPR - Center for Economic Policy Research - CEPR); Thierry Mayer (ECON - Département d'économie (Sciences Po) - Sciences Po - Sciences Po - CNRS - Centre National de la Recherche Scientifique) |
| Abstract: | Using an instrument based on a national contest in France determining researchers' location, we find evidence of peer effects in academia, when focusing on precise groups of senders (producing the spillovers) and receivers (benefiting from the spillovers), defined based on field of specialisation, gender and age. These peer effects are shown to exist even outside formal co-authorship relationships. Furthermore, the match between the characteristics of senders and receivers plays a critical role. In particular, men benefit a lot from peer effects provided by men, while all other types of gender combinations produce spillovers twice as small. |
| Keywords: | Economics of Science,Peer Effects,Research Productivity,Gender Publication Gap |
| Date: | 2019–11–01 |
| URL: | http://d.repec.org/n?u=RePEc:hal:wpaper:hal-03393072&r= |
| By: | Quynh Hoang (DIAL - Développement, institutions et analyses de long terme, IRD - Institut de Recherche pour le Développement); Camille Saint Macary (DIAL - Développement, institutions et analyses de long terme, LEDa - Laboratoire d'Economie de Dauphine - IRD - Institut de Recherche pour le Développement - Université Paris Dauphine-PSL - PSL - Université Paris sciences et lettres - CNRS - Centre National de la Recherche Scientifique, IRD - Institut de Recherche pour le Développement); Laure Pasquier-Doumer (DIAL - Développement, institutions et analyses de long terme, LEDa - Laboratoire d'Economie de Dauphine - IRD - Institut de Recherche pour le Développement - Université Paris Dauphine-PSL - PSL - Université Paris sciences et lettres - CNRS - Centre National de la Recherche Scientifique, IRD - Institut de Recherche pour le Développement) |
| Abstract: | Ethnic inequality remains a persistent challenge for Viet Nam. This paper aims at better understanding this ethnic gap through exploring the formation of risk sharing networks in rural areas. It first investigates the differences in risk sharing networks between the ethnic minorities and the Kinh majority, in terms of size and similarity attributes of the networks. Second, it relies on the concept of ethnic homophily in link formation to explain the mechanisms leading to those differences. In particular, it disentangles the effect of demographic and local distribution of ethnic groups on risk-sharing network formation from cultural and social distance between ethnic groups, while controlling for the disparities in the geographical environment. Results show that ethnic minorities have smaller and less diversified networks than the majority. This is partly explained by differences in wealth and in the geographical environment. But ethnicity also plays a direct role in risk-sharing network formation through the combination of preferences to form a link with people from the same ethnic group (in breeding homophily) and the relative size of ethnic groups conditioning the opportunities to form a link (baseline homophily). In breeding homophily is found to be stronger among the Kinh majority, leading to the exclusion of ethnic minorities from Kinh networks, which are supposed to be more efficient to cope with covariant risk because they are more diversified in the occupation and location of their members. This evidence suggests that inequalities among ethnic groups in Viet Nam are partly rooted in the cultural and social distances between them. |
| Abstract: | Les inégalités inter-ethniques demeurent un problème préoccupant au Viet Nam. Dans cet article, nous cherchons à mieux comprendre l'origine de ce phénomène en explorant la formation de réseaux de solidarité dans les zones rurales. Nous examinons d'abord quelles sont les différences de composition de ces réseaux entre les minorités ethniques et la majorité Kinh. Nous montrons que les minorités ethniques ont des réseaux plus petits et moins diversifiés que la majorité. Nous explorons ensuite les mécanismes à l'origine de ces différences, en nous appuyant sur le concept d'homophilie. Plus précisément, nous distinguons l'effet de la répartition démographique et locale des groupes ethniques de l'effet de la distance culturelle et sociale entre groupes ethniques, ou autrement dit des préférences à former un lien avec des personnes du même groupe ethnique. Nous montrons que les différences de composition des réseaux de solidarité s'expliquent en partie par les écarts de richesse entre les groupes ethniques et des 2 environnements géographiques différents. Mais l'ethnicité joue toutefois un rôle direct dans la formation de ces réseaux à travers un effet combiné de préférences à se lier avec des personnes de la même ethnie et de composition démographique différenciées selon les groupes ethniques. Les préférences à se lier avec des personnes du même groupe ethnique sont plus fortes chez les Kinh majoritaires, ce qui entraîne l'exclusion des minorités ethniques des réseaux Kinh, supposés être plus efficaces pour faire face à des risques covariants car ils sont plus diversifiés dans l'occupation et la localisation de leurs membres. Ces résultats suggèrent que les inégalités entre les groupes ethniques au Viet Nam sont en partie enracinées dans les distances culturelles et sociales qui les séparent. |
| Keywords: | Réseau de solidarité,homophilie,inégalités inter-ethniques,homophily,ethnic gap,Viet Nam,Risk-sharing network,Vietnam |
| Date: | 2021–10–01 |
| URL: | http://d.repec.org/n?u=RePEc:hal:wpaper:hal-03361332&r= |