I found this wee gem on CMC under training. The second half is very interesting. It has implications for gold testing 1240 support.
https://www.youtube.com/watch?v=4-LZQOwL7ww&t=0s&list=PL11BBCA6710420656&index=20
The signal for this trade is a price foray outside the Bollinger Bands followed by a candle closing back inside them when they are not expanding in width.
The indicator below the chart is Bollinger Band width, which measures volatility. When price moves outside the BBs, it is more than two standard deviations from the mean. Statistically speaking this is a rare event and, on average, price will then drift back towards the mean. However price tends to move back towards the mean only if BB width is contracting or flat, which means the BBs are not expanding to accommodate further volatility (bright green lines). If the BBs are expanding it means they are accommodating the volatility and price is not ready to return to the mean yet (red lines).
This method suggested the onset of a gold short from 25 October, a long from 15 November, and the pullback to around 1234 on 14 December (bright green lines).
This works well for platinum too. Again price drifts towards the mean when BBs are flat to contracting. Price can keep pushing outside the BBs when they expand to accommodate it.
