Great links and I really appreciated your smart note, Brad Case, on volatility. I was going to ask how you defined volatility (because so much of the press just throws the term around, as you well know). Sure enough, you share at the end: "volatilities are computed using a dynamic conditional correlation model with generalized autoregressive conditional heteroscedasticity (DCC-GARCH, developed by Nobel prize-winning economist Robert Engle). DCC-GARCH is pretty much the state of the art for this sort of analysis because it’s both accurate and sensitive to the most recent market conditions. The model is estimated using daily data, but weekly data show a very similar pattern."