Volatility measures

[alexnovitzky]

Hi All,

I am trying to measure the volatility of the variables below. I'm not sure when i should be using first difference, log, or log difference. Can someone please explain this to me?

Thanks


LT Interest Rate
ST Interest Rate
Relative Equity Return (using 2 stock indices)
GDP Growth spread between 2 countries
M2/GDP
Dom Credit/GDP
Foreign Reserves/GDP