CYCLES

Sometimes Now And Sometimes Then

When To Trade With Cycles

by John F. Ehlers
When should you trade the cycle mode in a market and when should you trade the trend mode? Find out with this indicator.

IN theory, trading with cycles is easy -- just buy at the valley and sell at the crest. This is just a variation of the old buy-low, sell-high dictum. In practice, however, trading with cycles is far more difficult. Just for openers, the very existence of market cycles is ephemeral and we must jump on them quickly to take advantage of any market inefficiency they represent. This is demonstrated by the Mesa8 measurement of the historical spectra of the Standard & Poor's futures contract seen in Figure 1. The spectra are shown colorized over a 20-decibel range from white-hot, through red-hot, to ice-cold. Colorizing this way enables the display in a subgraph in synchronism with the bar chart. Figure 1 clearly shows how the dominant cycle in the data varies with time.

FIGURE 1: MESA8-MEASURED SPECTRA. On this chart of the S&P futures contract you can see that the dominant cycle in the data varies with time.

In addition, there are a number of other conditions that make trading with cycles more difficult besides temporal variability, perhaps to the point that the real question is, "When should I not trade with cycles?" The most significant among these conditions are signal to noise ratios, being swamped by the trend, and trend persistence.

SIGNAL TO NOISE RATIO

One of the purposes of measuring the market cycle is to determine market inefficiency because of a short-term coherence. If there is a coherence in prices, we can expect that coherence to continue, at least for a short while. We can identify this cycle component as the signal we are trying to exploit. On the other hand, the market is composed of a large number of traders with diverse objectives. If we are looking for a cycle period on the order of a month, the daily fluctuation in price is noise that can interfere with our signal. In this sense we can define the range of a given price bar from low to high as noise. If the noise amplitude is equal to the peak amplitude of the cycle, then we have the theoretical case displayed in Figure 2.
 

...Continued in the April issue of Technical Analysis of STOCKS & COMMODITIES


Excerpted from an article originally published in the April 2007 issue of Technical Analysis of
STOCKS & COMMODITIES magazine. All rights reserved. © Copyright 2007, Technical Analysis, Inc.



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