Have you ever got any doubts, questions and comments on the measurement, correlations and usefulness of IV (Implied Volatility)? An options trader can predict two things to make profits: (Forecast) Volatility of the underlying; and (Future) Volatility of its options. Practically, general traders can only use Implied Volatility (based on options price) to project its own Future Volatility (against its own Historical Volatility of the options), as well as to project the Forecast Volatility of its underlying (against the 20-day Historical Volatility of the underlying). And their correlations (of both Historical Volatility measures) can be found 'many times not frequently highly correlated'. Obviously, an options price plays the most important role for the above dynamics. So the use of IV is basically a kind of: - Self-fulfilling prophecy? or - Faciltating manipulation of (options) prices? or - Both? or - Anything else?