The Detrended Price Oscillator ("DPO") attempts to
eliminate the trend in prices. Detrended prices allow you to more easily
identify cycles and overbought/oversold levels.
Interpretation
Long-term cycles are made up of a series of
short-term cycles. Analyzing these shorter term components of the
long-term cycles can be helpful in identifying major turning points in
the longer term cycle. The DPO helps you remove these longer-term cycles
from prices.
To calculate the DPO, you specify a time period.
Cycles longer than this time period are removed from prices, leaving the
shorter-term cycles.
Example
The following chart shows the 20-day DPO of Ryder.
You can see that minor peaks in the DPO coincided with minor peaks in
Ryder's price, but the longer-term price trend during June was not
reflected in the DPO. This is because the 20-day DPO removes cycles of
more than 20 days.
Calculation
To calculate the Detrended Price Oscillator, first
create an n-period simple moving average (where "n" is the number of
periods in the moving average).
Now, subtract the moving average "(n / 2) + 1" days
ago, from the closing price. The result is the DPO.