Investors repeatedly jump ship on a good strategy just because it hasn't worked so well lately, and, almost invariably, abandon it at precisely the wrong time.

I buy stocks when they are battered. I am strict with my discipline. I always buy stocks with low price-earnings ratios, low price-to-book value ratios and higher-than-average yield. Academic studies have shown that a strategy of buying out-of-favor stocks with low P/E, price-to-book and price-to-cash flow ratios outperforms the market pretty consistently over long periods of time.

We invest in undervalued companies that exhibit strong fundamentals, above-market dividend yields and historic earnings growth, which our analysis indicates will persist. Our strategy is to own strong, fundamentally sound companies and to avoid speculative stocks or potential bankruptcies.

Demanding immediate success invariably leads to playing the fads or fashions currently performing well rather than investing on a solid basis. A course of investment, once charted, should be given time to work out. Patience is a crucial but rare investment commodity.

If you have good stocks and you really know them, you'll make money if you're patient over three years or more.

Psychology is probably the most important factor in the market - and one that is least understood.

One of the big problems with growth investing is that we can't estimate earnings very well. I really want to buy growth at value prices. I always look at trailing earnings when I judge stocks.