How Important Is Investor Behavior to Long-Term Returns?

The Wilshire 5000 is something like 3400 stocks. It's even less than then it got up to 7000, believe it or not. But probably right now, 2500. We were cranking out a lot of new companies before we realized that pets.com wasn't a sustainable business. I also had an idea that growth might do better than value for young people investing on a dollar averaging basis and wouldn't be that much riskier. So I divided the S&P into two.