Collaborative Research: Social Networks and the Diffusion of Microfinance

小额信贷在过去十年中发展迅速，人们希望小额信贷有能力为数百万人提供获得资金的途径，从而使他们摆脱贫困。小额信贷之所以能成功地向穷人发放贷款（与之前政府资助的补贴信贷计划的失败形成对比），原因之一是它对当地社会网络的依赖。贷款通常提供给5至10名妇女组成的小组，她们共同承担贷款的责任。社交网络被用来传播有关小额信贷的信息，筛选不良借款人，并提供监控。本提案的目的是在理论上和经验上更详细地研究社会网络结构如何影响小额信贷组织成员的扩散。为此，我们将收集50个村庄村民之间社会关系的非常详细的信息，其中一个特定的小额信贷机构（BSS，卡纳塔克邦）计划在未来几个月内开始运作。我们还将收集有关村庄的具体特征（如地理特征）的信息，这些特征可能是这些网络结构外生变化的来源。随着BSS的扩大，BSS的信用部门将分享新成员的信息、小组是如何组成的以及小组的表现（还款、退出、参加会议等）。这些信息将与社会网络调查相匹配，使我们能够根据村庄中存在的网络的类型和形状，绘制出村庄内和村庄间小额信贷网络的扩散图。我们将利用这些信息来回答有关社会网络在小额信贷中的作用的几个重要问题：首先，网络结构对小额信贷扩散方式的影响是什么？其次，一些特定的网络成员提前加入是否重要？第三，小额信贷是否排除了一些非社会网络中心的人？第四，拥有更多人脉的个人是否也更可靠？为了构建这些问题，我们将依靠现有的关于社会网络结构对信息扩散影响的理论结果，这些结果是由本提案中的一些pi贡献的。我们还将开发新的成果，以阐明尚未在理论上探索的问题。该项目具有科学和实际意义。在科学层面上，小额信贷依赖于社会网络来传播信息，同时也是有效运作的基础，这是一个有趣的领域，可以用来测试一些现代网络理论。在实践层面，小额信贷被广泛认为是利用社会网络向穷人提供信贷的有效途径之一。但是，对于村庄间社会网络的变化如何影响小额信贷组织在村庄中传播的能力、它们排除或包括一些人口的倾向，以及它们的运作效率如何，人们知之甚少。对这些问题的回答可以为小额信贷从业人员和担心小额信贷可能排斥社会边缘人群的决策者提供重要的实用建议。

Microfinance has spread very rapidly in the last decade, raising the hope that it has the power to lift millions out of poverty by providing them with access to capital. A source of the success of microfinance in successfully making loans to the poor (in contrast to the failures of previous government-sponsored subsidized credit schemes) is its reliance on the local social network. Loans are often given to group of five to ten women who are jointly liable for the loan to the group. The social networks are harnessed to diffuse information about micro-finance, screen out bad borrowers, and provide monitoring. The goal of this proposal is to examine in more details, both theoretically and empirically, how the social network structure impacts the diffusion of membership in a microfinance organization. To this end, we will collect very detailed information on social ties between villagers in 50 villages where a specific microfinance institution (BSS, in Karnataka) is planning to start work in the next few months. We will also collect information on specific features of the villages (such as geographical features) which may be a source of exogenous variation in the structure of these networks. As BSS expands, the BSS credit department will share information on those who become members, on how groups are formed, and on the performance of the groups (repayment, drop out, meeting attendance, etc.). This information will be matched with the social network survey, allowing us to map the diffusion of microfinance both along networks within a village and across villages, depending on the type and shape of networks present in the village.We will use this information to answer several important questions on the role of social networks in Microfinance: First, what is the impact of the structure of the network on the way microfinance diffuses? Second does it matter that some specific members of the network join early? Third, does microfinance exclude some people who are not central to the social network? Fourth, are individuals who have more connections also more reliable borrowers? To frame these questions, we will rely on existing theoretical results on the impact of social network structure on the diffusion of information which have been contributed by some of the PIs on this proposal. We will also develop new results to shed light on issues that have not yet been explored theoretically. The project has scientific and practical implications. At the scientific level, microfinance, which relies on social networks both to spread information as well as a basis for effective functioning is an interesting area for testing some of the modern theory of networks. At the practical level, microfinance has been widely heralded as one of the effective ways to harness social networks to reach the poor with credit. But little is known on how variations in social networks across villages impact the ability of microfinance organizations to spread in villages, their tendency to exclude or include some pockets of the population, and how effectively they function. Answers to those questions can lead to important practical advice for microfinance practitioners and for policy makers who are concerned that microfinance could exclude socially marginalized populations.