In his latest column for Seeking Alpha, Validea CEO John Reese looks at how Warren Buffett — and other gurus — have gone about identifying companies with “economic moats”.

“While Buffett (upon whom I base one of my Guru Strategies) has popularized the “moat” concept, he isn’t the only guru who targeted moat-encircled companies,” Reese writes. “Kenneth Fisher, whose book Super Stocks is the basis for another of my strategies wrote that the ‘super companies’ he looked for needed to have an ‘unfair advantage’ – that is, ‘a competitive superiority over all current or potential competitors,’ which can come from a powerful brand name, status as the industry’s low-cost producer, or a patent on a particular product or technology. Hedge fund guru Joel Greenblatt, whose Little Book that Beats the Market is the basis for another of my models, similarly talks about a ‘special advantage,’ one that keeps competitors from destroying a firm’s ability to earn strong profits. Examples of such advantages, he says, are strong brand names, excellent competitive position, or a new top-notch product.”

While finding firms with enduring advantages may seem to be a qualitative endeavor, Reese says that Buffett, Fisher, and Greenblatt each has said this sort of business advantage often manifests itself in metrics that you can find on a balance sheet, income statement, or a stock’s fundamentals. He looks at the metrics they used to identify enduring/special/unfair advantages, and five stocks that currently appear to have moats based on those metrics. Among them: Winnebago Industries.