During this week, I have been reading and thinking more about how to measure social capital. In the literature, there is no agreed upon definition of social capital nor is there any agreed upon method for measuring it. Therefore, proximal indicators are used to measure some believably related contributor to social capital.
For instance, Putnam has used the density of voluntary organizations (VOs) in a community to measure social capital. So, in this case, the density of VOs is a proximal indicator for social capital.
Nan Lin uses the number of connections an individual has weighted by the importance of the person.
Social Capital Survey Reading:
Social Capital: One or Many? by Martin Paldam (Economist)
Social Capital Survey by Tristan Claridge (in particular, see measurement)