Investors are continually attracted tho “glamour stocks” — those popular, flashy picks that are always being talked about. But quantitative investing guru James O’Shaughnessy says history shows those exciting stocks usually lead to big trouble.

In a recent CNBC interview, O’Shaughnessy talks about how stocks that were cheapest based on a composite of value factors far outperformed the market from 1963-2013 — and how pricey “glamour stocks”, which are “priced to absolute perfection”, he says, far underperformed the market. In fact, a $10,000 investment in the highest-valuation stocks in 1963 would have shrunk to less than $3,000 (inflation-adjusted) by the end of 2013, he says.

O’Shaughnessy also discusses how his value composite metric works, and he offers a key broader point: Investors who can’t commit to being in stocks for at least five years shouldn’t be buying stocks, he says.