The Commodity Selection Index ("CSI") is a momentum
indicator. It was developed by Welles Wilder and is presented in his
book New Concepts in Technical Trading Systems.
The name of the index reflects its primary purpose.
That is, to help select commodities suitable for short-term trading.
Interpretation
A high CSI rating indicates that the commodity has
strong trending and volatility characteristics. The trending
characteristics are brought out by the Directional Movement factor in
the calculation--the volatility characteristic by the Average True Range
factor.
Wilder's approach is to trade commodities with high
CSI values (relative to other commodities). Because these commodities
are highly volatile, they have the potential to make the "most money in
the shortest period of time." High CSI values imply trending
characteristics which make it easier to trade the security.
The Commodity Selection Index is designed for
short-term traders who can handle the risks associated with highly
volatile markets.
Example
The following chart shows the Japanese Yen and its
14-day CSI. Strong volatility and strong trends result in high CSI
values at points "A" and "B."
Calculation
It is beyond the scope of this book to provide full
calculation details on the Commodity Selection Index. It is calculated
using the ADXR component of the Directional Movement indicator. Wilder's
book New Concepts in Technical Trading Systems contains detailed
information on the calculation of the CSI.