Going through my old computer files and ran across this paper that I have 95% written, but just cannot seem to get myself to finish:
An economy is a complex flow system with the conserved quantity “value” moving either between agents in the system or between an external environment and the agents. While it would be very difficult to derive the entirety of flow for an economy such as that of the United States, it is possible to observe the flows for a coarsed-grained repre- sentation of the economy. The U.S. Bureau of Labor Statistics gathers this data and produces a yearly series of tables called Inter-Industry relationship matrices to represent these flows. These matrices are an empirical observation of the financial interactions between sectors for any given year. With this data, it is possible to derive a variety of properties for the economy. This paper takes two sets of Input-Output data (one from 1983-2000 and one from 1998-2006) and studies two important sector measures originally used in ecological modelling. The first is the trophic level, a measure of how dependent a sector is on other sectors within the system. The other is the anti-trophic level, a measure of how dependent the system is on a given sector. From these measures, the effects of specific policy changes on specific indus- tries becomes startlingly apparent, and a new tool to see critical phase shifts as they happen is described.
I don’t really know why. It’s got some pretty good graphs and makes some interesting predictions based on similar models to watershed fish stocks and such.
Hmm, maybe one day I’ll find the time and try to get it into PNAS before it’s too late. 😛