It is possible to normalize an oscillator by dividing the values by a constant divisor. In the construction of his Commodity Channel Index (CCI), Donald R. Lambert compares the current price with a moving average over a selected time span—usually 20 days. He then normalizes the oscillator values by using a divisor based on mean deviation. As a result, the CCI fluctuates in a con­stant range from +100 on the upside to –100 on the downside. Lambert recommended long positions in those markets with val­ues over +100. Markets with CCI values below –100 were candi­dates for short sales.It seems, however, that most chartists use CCI simply as an overbought/oversold oscillator. Used in that fashion readings over +100 are considered overbought and under —100 are oversold. While the Commodity Channel Index was originally developed for commodities, it is also used for trading stock index futures and options like the S&P 100 (OEX). Although 20 days is the common default value for CCI, the user can vary the number to adjust its sensitivity.