Why Personal Ties Cannot Be Bought
通过一个劳动力市场模型，分析个人关系网络在传递不可观测的生产力信号中的作用，探讨为何市场机制难以替代自发形成的人际纽带，对理解种族聚居区、海外华人经济等现象有启发。
Personal connections can function as privileged channels of information and trust. When the reliability of information is particularly important applying for a job, needing capital for a new enterprise, moving to a new country their role often becomes crucial. Hence the ethnic enclaves, both residential and professional, in New York City; the economic weight of the Overseas Chinese in their countries of residence; the success of Medieval networks of merchants, organized along ethnic or religious lines. Personal networks are often very successful, but they are by their nature discriminatory and thus tend to generate resentment and opposition among those excluded. Economists and sociologists debate whether networks can be replicated artificially. Not surprisingly, economists tend to be more optimistic, believing that appropriate market mechanisms, encouraged and supported by policy where necessary, can substitute for the missing personal channels. Sociologists on the other hand, see the personal, spontaneous link as the essence of the relation, and thus as something that by its nature cannot be replicated at will (e.g. Marta Tienda and Rebeca Raijman (2001), discussing James E. Rauch (2001)). We address this question in a simple model of labor markets where workers differ in their unobservable productivity. We ask how signaling the possibility of engaging