Investors should be skeptical of history-based models. Constructed by a nerdy-sounding priesthood using esoteric terms such as beta, gamma, sigma and the like, these models tend to look impressive. Too often, though, investors forget to examine the assumptions behind the models. Beware of geeks bearing formulas.
Warren BuffettI knew a lot about what I did when I was 20. I had read a lot, and I aspired to learn everything I could about the subject.
Warren Buffett