Counting the Uncountable: Investigations into Social Networks

每当有人说“我们这里有问题，我们需要用公共资金来解决它”时，他们问的第一个问题是“这个问题有多严重——有多少人受到影响？”目前的研究将改进一种被称为“网络放大”的新方法，用于估计难以统计的人口的规模，比如无家可归者和各种犯罪的受害者。网络放大法包括询问人们在各种已知规模的人群中他们认识多少人。网络放大方法的一个困难是，人们经常高估他们对小群体成员的了解，而低估他们对大群体成员的了解。漏报可能是因为人们没有意识到他们认识的人实际上是特定群体的一员，而漏报可能是因为人们被迫为他们对群体的了解选择一个特定的数字，并进行猜测。在这个项目中，我们将使用焦点小组和网络调查来提供对这些影响的维度的定性理解。网络调查将产生关于人们相互了解某些事情的概率的信息。例如，人们通常知道他们每个熟人的职业，但不太可能知道他们的熟人有一个双胞胎兄弟姐妹。从本研究中得到的概率将提高网络放大方法在估计未知人口规模时的准确性。然后，我们将进行全国性的、有代表性的调查，以纳入和测试该方法的改进。

Whenever someone says `we have a problem here, and we need to spend public money to fix it` the first question asked is `how big is this problem -- how many people are affected by it?` The current research will improve a new method -- called the `network scale-up` -- for estimating the size of hard-to-count populations like the homeless and victims of various kinds of crime. The network scale-up method involves asking people how many people they know in various populations whose size is well known. One difficulty with the network scale-up method is that people often over-report their knowledge about members of small populations and under-report their knowledge about members of large populations. Under-reporting may occur because people are unaware that someone they know is, in fact, a member of a specific population, while over-reporting may occur when people are forced to choose a specific number for their knowledge of a population, and guess. In this project, we will use focus groups and a network survey to provide a qualitative understanding of the dimensions of these effects. The network survey will produce information about the probability that people know certain kinds of things about each other. For example, people often know the occupations of each of their acquaintances, but are less likely to know that their acquaintances have a twin sibling. The probabilities derived from this research will enhance the accuracy of the network scale-up method for estimating the size of populations whose size is not known. We will then conduct national, representative surveys to incorporate and test refinements of the method.