(The following applies to technical indicators in the public domain.) (1) The vast majority of technical indicators are too weak to provide an edge. If they weren't weak, they wouldn't be free. Think about it. (2) The majority of technical indicators are hodgepodge formulae with little basis in logic. Just because something is arcane and "complicated", that doesn't automatically make it valuable. (3) There's a reason why there are no performance stats in the vast majority of TA books.