BALTIMORE ( Stockpickr) -- Warren Buffett's got a secret. It's a value investing metric that too many investors ignore today -- and it's spitting out a handful of stocks right now that are worth buying.The metric? It's book value growth. Sure, plenty of investors look at book value stats (book value per share and price-to-book are the two most popular), but most use it to measure a company's book value at a specific point in time: now. Instead, looking at how book value changes over time can tip investors off to firms that are creating the most real fundamental value for shareholders, no matter what's going on in the stock market. >>5 Stocks to Buy to Be Like Buffett Book value growth is a metric that's highly thought of by legendary value investors such as Buffett and Ben Graham -- and it's a stat that Buffett's own Berkshire Hathaway ( BRK.B) has embodied. The firm has generated annualized book value growth of 19.8% since 1965, besting the S&P 500 by more than double. Of course we're not looking at book value growth per share in a vacuum. Other factors favored by Buffett, such as a bargain price-to-earnings ratio, and tenable sales trajectory factored into these names as well. >>5 Cash-Rich Companies to Buy This Fall With that, here's a look at five other stocks that fit that book value growth mold.