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All About Moving Averages
There is probably more actual money being traded
today using moving averages than with all other technical indicators
combined. Because they can be used for everything from finding
very long-term monthly trends to setting stops for daytrading,
and for anything in between, moving averages have been the subject
of more discussion in technical literature and elsewhere than
any other study. One reason they enjoy such popularity is when
the markets trend, these simple little lines work as well or better
than indicators, which require a Ph.D. to interpret.
Moving averages smooth out market fluctuations and short-term
volatility and give the trader
some indication on which way financial market is
going. Just as important is what they don't do. Unless you plot
them as an oscillator, they provide no overbought/oversold information
at all.
They are trend-following indicators of the purest sense. They
show the direction of a trend, yet they don't measure how strong
or weak the trend is. Their function is to identify the direction
of the trend and then smooth out or dampen its volatility. Moving
averages do these things very simply and very well.
Types of Moving Averages
There are so many possible types and combinations of moving
averages that it is impossible to list them all. Most of the more
exotic moving average varieties were created in the 1970's, when moving averages
were considered to be very sophisticated and advanced technical
analysis tools.
Today, a lot of talented and creative
virtual trader market technicians spend most of their
time figuring out new ways to improve and trade moving averages.
This interest in moving averages was well rewarded in the past, during
times of endlessly trending markets, when moving averages worked
extremely well. Most of the more inventive types have since fallen
into disuse (like Maxwell's "modified accumulative"
or "average-modified"). Three major categories have
survived the test of time: simple, weighted and exponential.
Simple Moving Averages
The simple moving average is calculated by adding and then averaging
a set of numbers (usually daily closes) representing market action
over some specified period of time. The oldest data point is dropped
as a new one appears; thus the average 'moves' and follows the
market. A line connecting the daily averages will have the effect
of smoothing recent market volatility. A large data set representing
a large amount of past data will create a smooth line. A smaller
data set representing only more recent data will create a more
responsive line.
Weighted Moving Averages
The simple moving average gives equal weight to each point in
the set of back data. The weighted moving average assigns greater
importance to more recent data by weighting each day's data differently.
This is usually done by multiplying the most recent data point
by a given number, adding the result to the overall calculation,
then multiplying the next most recent point by a lesser number,
and so on. The resulting line will be more responsive to recent
market activity than the simple moving average.
Exponential Moving Averages
The simple and weighted moving averages are only capable of
reflecting the data in the number of data points chosen for the
calculation. The exponential moving average assigns greater importance
to more recent market action like the weighted moving average.
It also takes into account all of the data in the data set, leaving
nothing out. A daily exponential moving average uses the life
of a futures contract. A weekly or monthly exponential moving
average uses as much data as you give it.
Despite the seeming sophistication of weighted and exponential
moving averages, nearly every test we've seen or done ourselves
has shown the simple moving average to be superior to the others
in terms of trading results. Our own research indicates that weighting
the data to emphasize recent events makes the indicator overly
sensitive, negating the original purpose of the moving average:
to smooth out market action.
Weighted and exponential moving averages tend to generate more
trades in tight, trading-range markets than simple moving averages.
The result is usually costly whipsaws. We recommend using simple
moving averages only. Save your system's complexity for other
things, like money management and risk control.
Multiple Moving Averages
Moving average based futures market or
stock market daytrading systems can use either a single moving
average or any number of moving averages in various combinations.
We've used single, dual, triple, or even quadruple moving average
systems. We suppose that any multiple is possible, but the variations
with only three or four can easily become overly complex and frankly,
we see no advantage to using anything more complicated than necessary.
Single Moving Average Systems
The simplest and often the most effective moving average is
the single moving average. It is most useful as a long-term trend
indicator, rather than as a daily trading device. For example
Colby and Meyers, in their book The Encyclopedia of Technical
Market Indicators, optimized for a single moving average over
75-years of monthly NYSE data, using a simple reversal system.
They found 12-months to be the optimum number, beating a buy-and-hold
strategy by a large margin. In our experience, this simple 12-month
moving average is a stock market timing device that's hard to
beat.
The basic rules for trading with a single moving average are
simple: buy when prices rise above the average, sell when prices
drop below the average. This results in a simple reversal system
that is always in the market. As you might imagine, a reversal
system is very susceptible to whipsaws and should only be used
as a long-term trend indicator.
Dual Moving Averages
The most popular moving average systems use two moving averages.
These generally consist of a longer-term average that serves to
define the trend, and a shorter-term average that gives trading
signals as it crosses the longer-term average. The best known
of these is Richard Donchian's 5-day vs. 20-day system.
Most research we've seen shows that dual moving average systems
tend to be more profitable than other types. The research also
shows that they, like just about all moving average systems, have
their ups and downs. They are notorious for giving back too much
of their hard earned profits. Anyone who traded Donchian's system
(which, by the way, is not a simple reversal system, but uses
an elaborate set of filters) during the trending 1970's made regular
and substantial profits. The same system lost heavily during the
middle and late 1980's. The basic signal with two moving averages
is the crossover. Buy when the shorter average crosses over the
longer, and sell when the opposite occurs.
Three Moving Averages
The most popular triple moving average is the widely followed
4-9-18-day method popularized by R. C. Allen in the early 1970's.
The third moving average opens up a huge number of potential trading
possibilities.
Generally speaking, when a market has bottomed the major indication
of a trend change is the 4-day crossing the 18-day. The confirming
signal is the 9-day crossing the 18-day. As prices peak, the preliminary
indication of a possible trend change will be the 4-day crossing
the 9-day. This may be an early point to take profits. The trend
reversal will be completed only when the 4-day and the 9-day cross
the 18-day.
We like the triple moving average systems because they offer
the advantage of a neutral zone as opposed to the reversal trading
called for by the single or double moving average methods.
For example, in the 4-9-18 system discussed above, when the 4
crosses the 9 we exit our position and we don't take a new position
in the market until the 9 crosses the 18.
We also like the triple system because the 4 crossing the 9 is
a quick profit taking mechanism that overcomes some of the problem
of giving back too much profit that we mentioned before. We believe
that exits should always be quicker than entries in a successful
trading system.
Four Moving Averages - Overkill?
Using four moving averages is neither as strange nor as difficult
as it sounds. Used properly, the four moving average approach
addresses some of the problems inherent in moving averages while
losing none of the advantages. The method uses the four moving
averages in sets of two. The two longest moving averages are used
strictly as trend identifiers and are most easily utilized when
set up as an oscillator moving about on either side of a zero
line. The two shorter moving averages are more sensitive and are
used for timing the entries and exits (usually on a crossover
basis) only in the direction of the longer-term dual oscillator.
Trades against the trend are, by definition, filtered out. If
an uptrend exists (as defined by the longer-term oscillator) only
long trades will be taken as signaled by the shorter-term crossovers.
Conversely, only short trades will be taken in a downtrend. There
will be neutral periods during trend corrections. There will also
be neutral periods during sideways markets. Whipsaws will not
be eliminated, but they will be significantly decreased.
Trading Filters
Most traders use a variety of filters to decide if the initial
signal is valid. Filters come in two categories: price filters
and time filters.
1. Filtering signals by price normally means waiting for the
price to meet some additional criteria before entering the trade.
This might be determined by measuring the amount the price has
penetrated the moving average or measuring the distance that one
moving average has crossed over another. The trader in this instance
is looking for confirmation that the moving average crossing was
not a random price event but is indeed a trend change. The new
trade is not taken until the price has exceeded the moving average
by a minimum amount. Another variation of this filter would be
waiting for prices to move by a given percentage after a crossover.
Our favorite filter or confirmation method is simple: wait until
you get a close in the new trend direction.
2. Time filters involve waiting a number of time periods after
the crossover before trading in the new direction. Many moving
average traders have observed that most of the whipsaws are very
immediate and a slight delay in entry can avoid most of them.
The waiting period would typically be from one to five-days. If
the price stays on the new side of the moving average for the
minimum time period, it is assumed that the signal was valid.
Obviously the waiting period will tend to reduce whipsaws, but
it may also give such a late entry that a major portion of a move
may missed.
Which Moving Average To Use?
There is no real answer to the question of what combination
of moving averages works best. We once saw a matrix, which contained
the year-by-year results of every moving average crossover between
1 and 100 going back for 15-years. The conclusion of this study
was that moving averages only worked if you knew in advance which
combination to use in each commodity each year. Frank Hochheimer
did the largest published trading test results we're aware of in
the early 1980's at Merrill Lynch.
We have done considerable work in this area ourselves and have
tested hundreds of thousands of moving averages. We don't believe
there is a magic answer. In practically every case, moving average
values which worked well over past data just don't hold up well
in present-day trading. This holds true whether they were optimized
values or not. In testing, however, and in others where actual
trade listings were available, one phenomenon kept reappearing.
As obvious as it sounds, almost any moving average combination
is profitable if a market is trending, and almost no combination
will produce profits if a trading market is not trending. The answer therefore
is not in the search for the perfect moving average. It is in
the search for a reliable system that will isolate the markets
in which moving averages will be profitable. Then we want to trade
those markets in a manner calculated to capture the most profit
with least drawdown. Non-trending markets, as we have stated many
times before, should be avoided or traded using a counter trend
type of indicator.
How To Make a Moving Average "Work"
Moving averages are the simplest and most elegant trend-following
study available. Within their limits, they can also be very effective.
The limitations of moving average systems, however, can be severe.
Most markets spend more time consolidating than they do trending.
A non-trending market can be a tough, an even fatal test for the
most carefully chosen moving average trading system. Here are
some of our thoughts and conclusions on how to help a moving average
system survive.
1. Try to confine your trading to only the trending markets.
Diversification helps, but don't trade all markets indiscriminately.
At any one time, less than 50% of all markets can be defined as
trending. Most of the time the actual number is considerably less
than that. Find a way to objectively define a market as trending,
and only then apply moving averages. We recommend Wilder's DM1/ADX
as a reliable study that indicates the extent to which a market
is directional or trendless. A simple explanation is when the
ADX is rising, the market is trending, and when it is falling,
the market is directionless. We also believe the Commodity Channel
Index indicator has some applications as a tool for finding and
measuring trending markets.
2. Moving averages in general react too slowly to be useful for
exits. Use an alternative exit strategy. We think most common
mistake made with moving averages is using the same set of moving
averages for both entries and exits. If you use slow averages
you will do well on the entry side, but will be too slow to exit
and give back most of the profits. If you use faster moving averages,
you'll have better exits but find yourself getting whipsawed on
the trade entries.
reprinted with permission of Technical Traders
Bulletin & webtrading.com
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