What’s the Best Overbought / Oversold Indicator?

Now and then I get asked what are the best technical indicators to use in trading. I know some of you out there are endlessly hunting for the holy grail of technical indicators that’ll get you in and out of trades flawlessly every time. If you find it let me know, and in the meantime here are a few rules of thumb:

1) It’s never a good idea to make trading decisions based on a signal from a single indicator. Technical indicators work best when you use them together, and as one part of a broader trading plan.

2) The best trading plans are simple, using a small number of solid technical indicators along with a few other proven tools and techniques. Too many indicators on a chart confuses things, sometimes even giving contradicting signals.

3) Popular technical indicators are popular because they work (and also because if enough people use them, they can become a self-fulfilling prophecy).

4) And the most critical rule of thumb: It’s at least as important, if not more-so, to know how to use overbought / oversold indicators as it is to know which are the best to use.

That last point is significant, so let it sink in. A better question for this article might be What’s the best way to use overbought / oversold indicators in my trading practice?

As you might know, overbought / oversold oscillators are leading indicators. In other words, they try to predict what price will do in the future. For example, when a security that has been trending up for awhile dips down and an  indicator signals that the security is “oversold,” there’s a good chance that price will soon spring back up into the trend. A buying opportunity could be right around the corner.

But we don’t take it for granted that a signal from one single indicator, especially a leading indicator, is enough to get us into the trade. Securities can stay in an overbought or oversold condition for a long time. An overbought or oversold signal simply triggers us to keep an eye on a trending security to see if it actually does start to go back into the trend.

And if that happens, we look at a few other things to validate that this is a good trade.  Is there enough volume to show that there’s strength in the movement back into the trend? Is there significant resistance or support in the way that might keep us from making the trade? Is there any upcoming event around the security’s company, like an earnings announcement, that could throw off price unpredictably? Etc.

Getting back to the original question, which overbought / oversold indicator do I like best? In my trading, I mostly use the Williams %R. The Williams %R, a popular indicator created years ago by author and leading trading expert Larry Williams, works by showing the current closing price in relation to the high and low of the past N (typically 10) days. Readings on the indicator range from -100 to 0. Readings in the upper range, from about -10 to 0, indicate the security is extremely overbought while readings from about -90 to -100 suggest it’s extremely oversold.

When the Williams %R shows an extreme overbought or oversold condition in a trending security, it’s time to watch for that security to kick back into the trend, and then use your other trading tools and techniques to confirm whether this is another potential profitable trade.

If you want to know more about the Williams %R or other technical indicators, a good resource is The Equis International site