Bollinger Band Trade Filtering

In the spirit of my New Year's resolution to put my trading system on a diet, I've been exploring ways to more aggressively filter out unnecessary trades, boost my trading odds, lower spread costs, and generally fine-tune my system to optimize its performance.

One filtering method I've found that shows a lot of promise involves Bollinger Bands, but not in the way they're usually used. Until now I used Bollingers to identify points where the price was likely to begin a reversal from a (relatively) overbought or oversold position (in forex, all things are relative). But for my current trade filtering project, I'm using them to identify periods of low volatility, when the EUR/USD pair is trading within a narrower range.

The measurement I'm using to determine these periods is the distance between the upper and lower Bollinger Band. When the bands are further apart, the market tends to be in a more volatile, wider-ranging phase. My forex strategy works best in these types of periods (as do most trading systems, I suspect). When the bands are close together, volatility is lower and my system tends to accumulate losses and trading costs.

So what I've done is have my trades switched off when the Bollinger Bands are too close together; the optimal distance between them is something I've determined through a lot of backtesting. What I've found is that my trading odds and performance improve significantly, with fewer big drawdowns and pointless trades when the markets are in the doldrums. Of course, because Bollingers are a lagging indicator, I also miss some big breakouts when the market shifts back from low to high volatility. But I'm willing to live with that - consistent trading performance is far preferable in the long run, and there's nothing that can kills your morale more quickly than waiting out a series of bad trades when the market's drifting in no particular direction. The more of those ugly periods I can avoid, the better!

Related topics:
A Nice Bollinger Band Trade
Put Your Trading System on a Diet
The Quest for a "Kill Switch" Signal