Developed by Donald Lambert, the Commodity Channel Index (CCI) is an indicator designed to identify cyclical turns in currencies or commodities. There are 4 steps involved in the calculation of the CCI:

1. Calculate today's Typical Price (TP) = (H+L+C)/3 where H = high; L = low, and C = close.
2. Calculate today's 20-day Simple Moving Average of the Typical Price (SMATP).
3. Calculate today's Mean Deviation. First, calculate the absolute value of the difference between today's SMATP and the typical price for each of the past 20 days. Add all of these absolute values together and divide by 20 to find the Mean Deviation.
4. The final step is to apply the Typical Price (TP), the Simple Moving Average of the Typical Price (SMATP), the Mean Deviation and a Constant (.015) to the following formula:
   
   

For scaling purposes, Lambert set the constant at .015 to ensure that approximately 70 to 80 percent of CCI values would fall between -100 and +100. The CCI fluctuates above and below zero. The percentage of CCI values that fall between +100 and -100 will depend on the number of periods used. A shorter CCI will be more volatile with a smaller percentage of values between +100 and -100. Conversely, the more periods used to calculate the CCI, the higher the percentage of values between +100 and -100.

Lambert's trading guidelines for the CCI focused on movements above +100 and below -100 to generate buy and sell signals. Because about 70 to 80 percent of the CCI values are between +100 and -100, a buy or sell signal will be in force only 20 to 30 percent of the time. When the CCI moves above +100, a currency is considered to be entering into a strong uptrend and a buy signal is given. The position should be closed when the CCI moves back below +100. When the CCI moves below -100, the security is considered to be in a strong downtrend and a sell signal is given. The position should be closed when the CCI moves back above -100.

Since Lambert's original guidelines, traders have also found the CCI valuable for identifying reversals. The CCI is a versatile indicator capable of producing a wide array of buy and sell signals.

• CCI can be used to identify overbought and oversold levels. A currency would be deemed oversold when the CCI dips below -100 and overbought when it exceeds +100. From oversold levels, a buy signal might be given when the CCI moves back above -100. From overbought levels, a sell signal might be given when the CCI moved back below +100.

• As with most oscillators, divergences can also be applied to increase the robustness of signals. A positive divergence below -100 would increase the robustness of a signal based on a move back above -100. A negative divergence above +100 would increase the robustness of a signal based on a move back below +100.

• Trendline breaks can be used to generate signals. Trendlines can be drawn connecting the peaks and troughs. From oversold levels, an advance above -100 and trendline breakout could be considered bullish. From overbought levels, a decline below +100 and a trendline break could be considered bearish. Rex Takasugi has used this type of system to trade the Russell 2000.

Traders and investors use the CCI to help identify price reversals, price extremes and trend strength. As with most indicators, the CCI should be used in conjunction with other aspects of technical analysis. CCI fits into the momentum category of oscillators. In addition to momentum, volume indicators and the price chart may also influence a technical assessment.