I love it when I read forum entries from people suggesting trading strategies along the lines of:
- Enter long when the RSI(14) is above 50, the stochastic (14,5,3) has crossed positive, and the Williams %R(14) is rising from the oversold area
- Enter short when the RSI(14) is below 50, the stochastic (14,5,3) has crossed negative, and the Williams %R(14) is falling from the overbought area
(Disclaimer: I just made up that strategy, so don’t trade it without testing it first – the fact is though – I seriously doubt it works)
Look, there are many problems with calling something like this a strategy, but the one I want to discuss today is simply that each of these indicators belongs to the same class of indicator. The RSI, the stochastic and the Williams %R are all oscillators.
An oscillator is a momentum based indicator that moves above and below a horizontal axis representing a position of neutral momentum.
Now each of these three oscillators measures momentum slightly differently. RSI measures it through comparing the magnitude of higher closes to lower closes over a set period of price bars. The stochastic measures it showing where the current close fits relative to a high/low range over a set period of price bars. The Williams %R works on the same concept as the stochastic, showing the relationship between the current close and the high/low range set over a period of price bars, however it does so through a different formula.
Basically, all are measuring the same thing. Quite likely, you’ve added some extra complexity to your strategy that serves no useful purpose at all.
Is there ever a need for more than one oscillator? Possibly, yes. It depends on what you’re trying to achieve. You might use one for indicating oversold or overbought price areas, and a different one for indicating increasing or decreasing momentum. You might even use one indicator twice, with different parameters, to represent momentum over both a shorter and longer time period. In this case, it’s fine.
However, I suspect many traders when developing their trading approach don’t really think about it to this degree. I suspect most just slap an indicator on their chart for no other reason than their platform provides it, and then look through the price history to see whether it shows potential for profits.
In this case, they can probably benefit from removing any redundancy.
So, what indicator classes are there? With some exceptions, the majority will fit within one of these four classes:
- Trend indicators, such as moving averages, directional movement or trendlines.
- Volatility indicators, such as bollinger bands, average true range or standard deviation.
- Oscillators such as RSI, stochastics and Williams %R.
- Volume / Market Strength indicators, such as volume, on balance volume or money flow index.
Generally you shouldn’t need more than one indicator to determine trend, one to determine volatility, one to determine momentum, and one to measure volume. In many cases, through a study of price action, you can even eliminate those single indicators and determine trend, momentum and volatility through price alone. Of course, that’s not for all people.
What I encourage you to do is to look carefully at the indicators you’re using. Do you have more than one indicator from any of the indicator classes? If so, is there a valid reason for it, or is it simply redundancy that has slipped unnoticed into your trading strategy? More often than not, I’d suggest your strategy could benefit from removal of that extra redundancy. Trading is one business where ‘simple really is best’.