Williams %R: A Fast Oscillator and Its Trade-Offs
Williams %R, created by Larry Williams, is a momentum oscillator that shows where the current close sits relative to the highest high over a lookback period, usually 14. It is the mirror image of the fast stochastic.
Values range from 0 to minus 100. Readings near 0 mean price closed near the top of its recent range, and near minus 100 means near the bottom. Common thresholds are minus 20 for overbought and minus 80 for oversold.
It is a fast indicator, reacting quickly to changes. That produces early signals but many false ones. In a trending market, it can sit in the overbought zone for long periods, so selling at minus 20 repeatedly loses money.
Better uses acknowledge this. In a ranging market, reversals from the extreme zones can offer entries near boundaries, with a stop beyond the range. In a trend, a dip into the oversold area in an uptrend, followed by a recovery above minus 80, offers a pullback entry in the trend's direction.
Because it is nearly identical in information to the stochastic, there is no need to use both. Choose one and learn its behavior.
As with all oscillators, the level of the indicator matters less than the context in which the signal appears, including trend, structure, and nearby levels.
Practical step: apply it to a trending and a ranging section of a chart, and count how many signals worked in each.
Williams %R: A Fast Oscillator and Its Trade-Offs
Williams %R: A Fast Oscillator and Its Trade-Offs
It’s Fairman 
Re: Williams %R: A Fast Oscillator and Its Trade-Offs
The pullback use in a trend is the one that makes sense to me. Dip into oversold, then back above minus 80, in the direction of the higher timeframe. Fewer signals, but they make sense. To make it concrete, if the daily chart on EURUSD is trending up, wait for the 1 hour Williams %R to drop below minus 80 during a pullback, then enter when it crosses back above, with the stop under the pullback low. Skip it if the pullback has broken the last higher low, because then the trend structure itself is in question. Test it on your pair before using it, since the 14 period default isn't always best.
It’s Fairman 
Re: Williams %R: A Fast Oscillator and Its Trade-Offs
Good call on not running it with stochastics. It's basically the same information flipped upside down. If you already like stochastics, there's no reason to add Williams %R. If you're starting fresh, either is fine, but pick one. A useful exercise is to put both on a chart for a week just to see how closely they match, then remove one. It's a good reminder that a lot of indicators are variations of the same calculation. The edge doesn't come from the indicator, it comes from the context you use it in and the discipline of following the same rules every time.
It’s Fairman 