The McClellan Summation index is a market breath indicator based on the McClellan Oscillator and was developed by Sherman and Marian McClellan.

The interpretation of the McClellan Summation is similar to that of the McClellan Oscillator except that it is more suited to major trend reversals as it is a long-term version of the Oscillator.

The McClellans suggest the following rules for use with the Summation:

Look for major bottoms when the McClellan Summation drops under -1,300.

Look for major tops to occur when a divergence with the market occurs above a level of +1,600.

The beginning of a significant bull market is indicated when the McClellan Summation crosses above +1,900 after moving upward more than 3,600 points from its prior low.