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 United Parcel Service (NYSE: UPS) 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

United Parcel Service

13%

11.5%

17.3%

16.6%

FedEx (NYSE: FDX)

6.8%

1.5%

11.6%

10.3%

Expeditors International of Washington (Nasdaq: EXPD)

37.1%

44.7%

39.1%

35.3%

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

United Parcel Service has consistently produced nice ROIC, but is down more than four percentage points from three years ago. FedEx has declined more than three percentage points in the past five years and has consistently sat behind its major rival. Expeditors International, on the other hand, has regularly produced returns on invested capital well above our 12% threshold for attractiveness, and at least before the latest four quarters, the company had been able to consistently increase its ROIC, suggesting its competitive position was improving. The differences among these three are striking.

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.