Archive for July, 2009

July 16, 2009

Policy implications if we use Power Law distribution

I have been working on my first paper with the title “Can Power Law help us avoid highly improbable tail events?” the premise of the argument is that if some economic variables fall in the Power Law distribution then policies associated with those economic variables need to be handled differently. For example, I am taking the problem of the Icelandic Krona, I have written about the Icelandic Krona before and I am convinced that it follows a Power Law distribution.

If we know that ISK follows a power law distribution and future fluctuations in ISK are going to follow the Power Law distribution should the Icelandic state still use the currency in its current form? or should it switch over to a more stable currency say the Euro? this debate is on-going in Iceland and I am afraid people are viewing this decision with their political lense and not the economic lense.

Just a simple switch in the probability distribution of the ISK has some serious policy implications. Lets do a simple thought experiment: The Financial Supervisory Authority of Iceland used a 20% devaluation of the ISK as a basis to stress test the banks in Iceland, why did they choose 20% because they thought ISK followed a Gaussian Normal Distribution and a 20% devaluation is a 2 or 3 sigma event or a very low probability of occurance, however if we change the distribution to Power Law a 20% devaluation of the ISK has a much higher probability therefore they would have chosen a much higher deviation for the stress test say 50% this would have shown the true color of the Icelandic banks capital adequacy and vulnerability to wholesale funding. The question is if the stress test had been done in 2006 when Iceland had a mini crisis, the FSA could have put a stop to the aggressive borrowing by the Icelandic banks which in turn would have reduced the leverage of the companies in Iceland and the citizens.

So choosing the right probability distribution matters! atleast that is the basis for my PhD thesis lets hope the thesis could influence some policy choices.

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