The QQE (Quantitative Qualitative Estimator) indicator consists of a smoothed Relative Strength Index (RSI) indicator and two volatility-based trailing levels (fast and slow).

The Fast Trailing Level (TL) and Slow TL are constructed by calculating the average range of the smoothed RSI over n-periods and then further smoothing the average range using an additional n-periods Wilders smoothing function. This smoothed average range of RSI is then multiplied by the Fast and Slow average range Multipliers to calculate the final Fast and Slow Trailing Levels.

This version of QQE is also using RSX (a smoother RSI without a lag) in order to further purify the signals.