Fair Value Methodology

Stocks = P/E driven identity
Stock sector ETFs = Use S&P 500 model as baseline, then use last 12 months relative performance and assume either relative performance continues or reverts
Gold = regressions model with real interest rates as predictor
Commodities = regressions model with inflation expectations as predictor

S&P 500 Model

Fair Value = P/E Ratio*Forward Earnings
P/E Ratio = 1 / (US10yr treasury yield + Equity Risk Premium)
Equity Risk Premium can be thought of as the excess return over the risk-free rate (10yr yield). Read more here.

Gold Scatter

Commodities Scatter