Operating earnings for S&P 500 companies are expected to jump 37% this year to a level that s far closer to their 2006 peak than their 2008 trough. However, sales are expected to increase just 7% -- less than they declined last year.

An optimistic reading of those numbers suggests companies have gotten leaner, so that small increases in sales now beget big jumps in earnings. A pessimistic view is that the accounting behind operating earnings is far too flexible, allowing companies to report their good news when markets are rising and to save their bad news to report as a steep loss during a single, distant restructuring quarter. As-reported earnings, which are measured using stricter accounting, are expected to rise half as fast as operating earnings this year.

The truth, perhaps, is somewhere between those two views, but investors can protect themselves from the subjectivity of earnings by shopping for stocks using more stable signs of prosperity, like sales, book value and dividends. The three stocks below have price/sales and price/book ratios that are below average for their industries, and each carries a dividend yield of over 3%.

Caterpillar

Sales of big earth-moving machines fell off a cliff when the world economy slowed last year. Caterpillar booked revenue of $51.3 billion in 2008, but last year brought in just $32.4 million. Demand is slowly picking up, though. Analysts foresee Caterpillar s sales rising to $36.8 billion this year more than the company s current stock market value. High commodity prices and a weak U.S. dollar are helping sales of mining equipment, in particular. Also, much of last year s sales decline was the result of dealers selling down their inventories. If the recent resumption of economic growth holds, those inventories will have to be replenished, which means sales could exceed end demand for a while. Shares of Caterpillar yield 3.2%.

Sara Lee

Like J.M. Smucke, which I mentioned Monday, Sara Lee is cashing in on strong coffee sales. But although Smucker s top brand, Folgers, is likely benefitting from a consumer shift toward more coffee made at home and less bought on the run, Sara Lee is seeing strong growth from its international brands, particularly those popular in Brazil. Sara Lee has a strong balance sheet and is quickly building cash because of its recent sales of non-food product lines. The company could afford a larger dividend shares now yield 3.5% but management is instead repurchasing shares and, according to analysts, keeping watch for new food brands to buy.

Intel

The world s largest chip maker reported record revenues and gross margins for its fourth quarter. However, its shares trade at just 12 timed forecast 2010 earnings, a discount of close to 40% to the broad stock market. Perhaps investors feel that the company s current pace of success is unsustainable; or that the economy is due for another slowdown; or that consumer computing is gradually migrating to handheld devices, which, unlike desktop computers, aren t yet dominated by Intel chips. Meanwhile, the company has amassed cash equal to 11% of its stock market value, which makes its 3.2% dividend yield look like well less than it can afford.