The Magic of Moving Averages

Wednesday, July 2, 2008
Perhaps, the first indicator you’ve seen and used when you first started to trade Forex was Moving Average. For me it was that. Moving averages come in several forms — simple, weighted, exponential, smoothed, etc. And they present the most basic way to measure the current trend direction and to spot its change. At a first glance simple moving average indicator looks like a miraculous tool that is easy to use and can tell you where to enter a position and where to exit one. Let’s try to understand this indicator — is it really as good as it seems?

What moving average shows? No matter if it’s a simple, exponential or any other form of MA the only thing it’s showing is the average rate of the currency pair over a certain period of time, hence the name. For example, MA with a period set to 7 on a daily chart for any given bar will show the average price over the previous 7 bars (days). That’s not a magic, right? Various forms of moving average just influence the way to calculate the average value (to make the line look more smooth or sharp, or to throw out spikes), but in the end we get the averages of the previous periods.

So what happens when the current price crosses MA? Faster MA crosses slower MA? 3 MAs cross each other? The cross of the MA and a price or other MA (or any amount of other MAs) is usually considered as the buy/sell signal or at least a partial signal. Why? Because they really show a change in the trend. The problem is that the change could have happened long ago (up to the MA’s period bars ago). When the moving average is crossed by the price chart from below that simply means the current price became higher than the average price for the last N bars (where N is the period of MA) — that’s it and nothing else. If MA with a period of 7 days crosses MA with a period of 14 days from below that means that the average price in the last 7 days is higher than the average price during the last 14 days (the actual trend change here could happen up to 14 days ago). Some strategies employ even 5 moving averages cross — that won’t change the fact that the only thing you’ll know when such cross occurs is the ratio of the average price over 5 different periods.

So is there any point to use moving average? Yes, I think that the moving average is a good indicator, but not as a signal producer or a trend change indicator. What does it do best? It indicates the average price. So, it’s better to use it when you want to know the average price over a certain period. You can compare current price to the moving average to consider overbought/oversold state, measure the volatility comparing the price action with the large-period MAs, use the long-term moving averages as the support and resistance levels (because so many traders and even institutional traders use it in this way), etc.

Maybe that’s not a pleasant thing to know if you base your trading strategy on moving averages’ crosses, but the facts don’t lie and with more trading experience it becomes clear that moving averages can’t do magic and shouldn’t be used as an easy way to create another Forex strategy.