We'd all like to invest as successfully as the legendary Warren Buffett. He calculates return on invested capital 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 how 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 lands between 8% and 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 Procter & Gamble (NYSE: PG) 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

ROIC TTM

1 year ago

3 years ago

5 years ago

Procter & Gamble

10.6%

9.9%

9.3%

18.2%

Johnson & Johnson (NYSE: JNJ)

21.9%

21.1%

20.3%

30.2%

Kimberly-Clark (NYSE: KMB)

16.6%

14.6%

15.4%

15.6%

Source: Capital IQ, a division of Standard & Poor's.

Johnson & Johnson and Kimberly-Clark are giving us well above our desired 12% return on invested capital, and have maintained fairly steady returns over the past three years. Kimberly-Clark has kept a lower ROIC but done so more consistently than either of the others. J&J is well off the highs of five years ago, so I have to wonder what's causing the slowdown. Procter & Gamble has not met our 12% threshold for attractiveness for the past few periods but, after its decline from five years ago, we have seen steadily increasing returns. Have the economic moats at J&J and P&G eroded or can they re-establish their high returns of a few years ago?

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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Jim Royal, Ph.D., owns shares in P&G. Johnson & Johnson, Kimberly-Clark, and Procter & Gamble are Motley Fool Income Investor choices. The Fool owns shares of and has written covered calls on Procter & Gamble. Motley Fool Options has recommended a diagonal call position on Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. The Motley Fool has a disclosure policy.