David Aronson had studied technical analysis for 40 years and was a true believer. However, his faith in the effectiveness of technical analysis was shaken in the summer of 2000, just after the technology bubble burst.

At the time, Aronson, 61, worked as a proprietary trader for Spear, Leeds, and Kellogg and had been profitable for four years. He used standard technical analysis techniques — interpreting classic chart patterns and standard indicators such as the Relative Strength Index (RSI), which he now describes as "seat-of-the-pants analysis."