Network Formation and Peer Effects in the USAFA

美国足球协会的网络形成和同伴效应

• 批准号: 1024841
• 负责人: Guido Imbens
• 金额: $ 25.1万
• 依托单位: National Bureau of Economic Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1024841&HistoricalAwards=false
• 关键词: Network; Formation; Peer; Effects; USAFA

The PIs propose to study the formation of social networks. The project contains two components, one empirical, and one methodological. In the empirical component the PIs plan to collect new data on friendship links from cadets at the United States Airforce Academy (USAFA). These data will permit the PIs to investigate the mechanisms underlying peer effects. Earlier work by Carrell and West demonstrated, through randomized assignment of cadets to squadrons, the presence of peer effects. Their work suggested that cadets benefit from the presence in their squadron of other cadets who have slightly higher academic performance. Here the PIs will investigate the mechanisms behind these effects, and in particular whether those effects work through the formation of friendships and social networks.In the methodological component, the PIs plan to develop a new structural model for network formation in a finite population and develop Bayesian methods for conducting inference for such models. The model is a strategic model of network formation, which assumes that, starting with an empty network, a sequence of opportunities arises for pairs of individuals to form friendship links. Given the opportunity, both potential friends evaluate the utility they get from the link, given their and their friends' characteristics, and given the state of the network, and decide to form a friendship or not. After a sequence of opportunities the network is finalized. These models will allow for homophily where links are more likely to be form between similar individuals. The random assignment of cadets to the squadrons will allow the PIs to assess causal effects on network formation, e.g., whether changing the composition of the group affects the number of friendships and the degree of community in the squadron. A novel feature of these models is that the PIs allow the utility of a friendship link to depend on the number and nature of friendships already established.Broader Impacts:The study of social networks has become widespread in many disciplines. In this cross-disciplinary proposal with economists and a sociologist, the PIs plan to develop and illustrate new methods that will be of use for a variety of areas where social networks are studied.

PI建议研究社交网络的形成。 该项目包含两个组成部分，一个是经验，一个是方法。 在实证部分，PI计划从美国空军学院（USAFA）的学员那里收集关于友谊联系的新数据。 这些数据将允许PI调查同伴效应的潜在机制。 卡雷尔和韦斯特的早期研究通过随机分配学员到中队，证明了同伴效应的存在。 他们的工作表明，学员受益于中队中其他学习成绩略高的学员。 研究者们将探讨这些影响的机制，特别是这些影响是否通过友谊和社交网络的形成而发挥作用。在方法论部分，研究者们计划开发一种新的结构模型，用于在有限的人口中形成网络，并开发贝叶斯方法来对这种模型进行推理。 该模型是一个网络形成的战略模型，它假设，从一个空的网络开始，一系列的机会出现对个人形成友谊链接。 如果有机会，两个潜在的朋友都会评估他们从链接中获得的效用，考虑到他们和他们朋友的特征，以及网络的状态，并决定是否建立友谊。 经过一系列的机会，网络最终确定。 这些模型将考虑到同质性，即相似个体之间更有可能形成联系。 将学员随机分配到中队将使PI能够评估网络形成的因果影响，例如，改变团队的组成是否会影响中队中友谊的数量和社区的程度。 这些模型的一个新特性是PI允许友谊链接的效用取决于已经建立的友谊的数量和性质。更广泛的影响：对社交网络的研究已经在许多学科中变得广泛。 在这个与经济学家和社会学家的跨学科建议中，PI计划开发和说明新方法，这些方法将用于研究社交网络的各种领域。