Some links that might be useful in using the composite index :
The Aerodynamics Investments Inc site is the official Constance Brow site. So, instead of explaining, I thought that it would be useful to seek additional info there (the Composite index gallery is quite good)

The chart gallery : http://www.aeroinvest.com/chartgallery.htm
The composite index chart gallery : COMPOSITE INDEX - Aerodynamic Investments Inc