There are many ways
of using moving averages to trade but by far the
most common method is to trade when a short-term
moving average crosses over a longer term moving
average. For example, if the 10-day MA crosses
above the 30-day MA we typically assume that we
have a new buy signal.
Let's stop for a minute and think about what
exactly is occurring at the point of a
crossover. When the 10-day MA and the 30-day MA
are at the same price, the trend is not nearly
as clear as it should be. What we are really
observing at the crossover point is that the
average of the last 30 prices is exactly the
same as the average of the last 10 prices. If we
are looking for trends to trade, this equal
relationship of the two moving averages is not a
reliable or logical indication of a trend. In an
upward trending market the average prices over
the last 10 days should be much higher than the
average of the last 30 days. By implementing new
trades at crossover points we are limiting our
trading to points that may not clearly reflect
what we should be doing. For best results in a
trend-following system we want to be trading
when the trend is clear and reliable; not when
the trend is confused and questionable.
Instead of trading at crossovers we should be
implementing our trades when the moving averages
are parallel or when the short-term moving
average is moving farther away from the
longer-term moving average. Perhaps the short
term MA should remain a minimum of some units of
Average True Range above the longer term MA for
several days. I believe that this procedure
would give us more reliable and more frequent
entry signals in the direction of the prevailing
trend, which is exactly what we want. To
identify the most reliable trends we want to see
the slopes of various moving averages all moving
steadily in the same direction and not crossing
back and forth.
Take a look at a chart of any market with a
strong trend. You will see that the moving
averages are not crossing back and forth
repeatedly. They will be moving in the same
general direction in a more or less parallel
fashion. Now look at a chart of a non-trending
market. As this market moves sideways the moving
averages will be crossing back and forth very
frequently. Look at the implications of this
simple examination of the charts. If we are
trading the crossovers we will be trading most
frequently in non-trending markets and trading
most infrequently in strongly trending markets.
Is that what we want? No, it's obviously not
what we want. We want just the opposite. We want
frequent entry opportunities in trending markets
and we want to avoid as many trades as possible
in non-trending markets.
The error in the logic of trading moving
average crossovers also extends to some
interpretations of MACD (Moving Average
Convergence and Divergence) and DMI (Directional
Movement Indicator). If we are looking at MACD
we want to see both lines (each line reflects a
moving average relationship) moving in the same
direction. We don't want to see them crossing.
When looking at DMI we want to see the Plus DI
lines and the Minus DI lines moving in opposite
directions and definitely not crossing.
Remember, when the Plus DI and the Minus DI
lines intersect it is telling us that the market
is in balance and has no direction; the amount
of upward and downward directional movement are
exactly equal. What makes our favorite
indicator, the ADX, so effective is that it
rises only when the Plus DI and the Minus DI are
moving in opposite directions and the distance
between the two indicators is widening.
With a little thought and effort I'm sure we
can design some reliable entry signals that are
based on moving averages but avoid the typical
crossover signals. For example we could measure
the slope of several moving averages and when
all the averages slope upward we would have a
buy signal.
We could also measure the distance between
several moving averages and implement our trades
when the averages are all headed in the same
direction but start getting farther apart. This
procedure would give us a series of entry
signals within the same original trend. This
should provide an excellent entry and re-entry
strategy.
by Chuck |