If Siegel's theory has global implications, then the P/E ratios for iShares Brazil and Market Vectors Russia are not attractive enough when interest rates are taken into account. Whereas the U.S. has a three-month of just 0.13%, Brazil's three-month is at 12.2% and Russia's three-month is at 8.2%. On the other hand, it's equally plausible that central bank policy direction is a larger factor than the interest rate categories. If China achieves its aim of reasonable inflation and moderate growth, it will end its rate hiking campaign before too long. Same goes for India. When these events transpire, expect resource-rich ETFs like Brazil and South Africa to be leaders in the emerging market pack once more.