We'd all like to invest as successfully as the legendary Warren Buffett. He calculates return on invested capital (ROIC) to help determine whether a company has an economic moat -- the ability to earn returns on its money beyond that money's cost.

ROIC is perhaps the most important metric in value investing. By determining a company's ROIC, you can see how well it's using the cash you entrust to it, and whether it's actually creating value for you. Simply put, ROIC divides a company's operating profit by the amount of investment it took to get that profit:

ROIC = Net operating profit after taxes / Invested capital

This one-size-fits-all calculation cuts out many of the legal accounting tricks (such as excessive debt) that managers use to boost earnings numbers, and provides you with an apples-to-apples way to evaluate businesses, even across industries. The higher the ROIC, the more efficiently the company uses capital.

Ultimately, we're looking for companies that can invest their money at rates that are higher than the cost of capital, which for most businesses is from 8% to 12%. Ideally, we want to see ROIC greater than 12%, at minimum. We're also seeking a history of increasing returns, or at least steady returns, which indicate that the company's moat can withstand competitors' assaults.

Let's look at Transocean (NYSE: RIG) and two of its industry peers to see how efficiently they use capital. Here are the ROIC figures for each company over several time periods:

Company

TTM

1 Year Ago

3 Years Ago

5 Years Ago

Transocean

9.7%

13.9%

17.4%

3.9%

Noble (NYSE: NE)

19.8%

24.8%

20.5%

7.2%

Pride International (NYSE: PDE)

4.4%

11.5%

7.2%

2.5%

Source: Capital IQ, a division of Standard & Poor's. TTM = trailing 12 months.

The dependence of this industry on a commodity product is seen here. Transocean fails to offer us returns on invested capital of better than 12%, and the steady decline in those returns over the past three years is not encouraging. Noble offers us an attractive ROIC, but its returns have also declined from three years ago. Pride International offers still lower returns, and also shows declines from three years ago. An increase in the price of oil -- which makes exploration a more profitable activity for the oil majors -- would juice the ROIC of these drillers as well.

Businesses with consistently high ROIC are efficiently using capital. They can use their extra returns to buy back shares, further invest in their future success, or pay dividends to shareholders. (Warren Buffett especially likes that last part.)

To unearth more successful investments, dig a little deeper than the earnings headlines and check up on your companies' ROIC.

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James Royal does not own any of the companies mentioned. The Fool owns shares of Noble. Try any of our Foolish newsletter services free for 30 days. True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community. The Fool has a disclosure policy.