So, today I gave my first presentation of work that I have been doing on the evolution of hierarchy and community structure in international trade networks. I have included my slides below...you can also skip down to just below my slides and find a short description of the various plots (if you are interested)...feedback and comments are appreciated as always... Network Fragility Short)
Some additional thoughts on the CCC plots...
Below is the plot of the CCC for OECD countries from 1962-2009 using data from UN Comtrade. Grey bars represent U.S. recessions as defined by NBER. I will focus my discussion on this plot (the other is similar...one of the nice things about limiting analysis to OECD countries is that the results are not dependent on choice of data!). Note that five countries have yet to report for 2009.
The evolutionary theory that I am testing predicts that environmental change will cause an increase in the modularity of the trade network. Here modularity (really hierarchy) is measured by CCC. He (2010) supposes that U.S. recessions are an indicator of environmental change. I have a couple of issues with this. First, he is using U.S. recessions which may or may not be a good indicator of global recessions (to my knowledge there is not a universally accepted measure of global recessions). More importantly, while the CCC does indeed increase during recessions, the largest increases in the CCC seem to occur outside of recessions...see for example the entire decade of the 1960's! Generally speaking, the economic environment in which global trade is being conducted is constantly changing and forcing individuals and companies to adapt along with it. I think a better measure of environmental change is needed.
Not that this is the answer, but I think I will plot some measure of real oil price shocks against CCC ans see what that looks like...
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