The fact that there is a lot more variation than usual in the rate of return you can earn investing in different parts of the economy also backs up his case.

BBC: The UK productivity puzzle (cont'd)

But he said it is a different situation when one approaches asset class as a fundamental investment and add commodities to achieve a certain rate of return or Sharpe ratio.

FORBES: INTERVIEW: Inflation Should Not Be A Problem For U.S., Canada, Gold Prices To Rise -- Dundee's Murenbeeld