As we get into the core of earnings season, you might want to cross check the results a quarter ago -- along with the year-on-changes -- of the companies you're following. While we've traditionally looked at those year-on-year changes as the primary barometer of a company's performance, amid the global economic mire that we're still stuck in, the former comparison can tell us a lot.

Take oil services operative Weatherford (NYSE:WFT). Following Halliburton (NYSE:HAL), which reported better than expected results late last week, the Swiss-based Weatherford saw its quarterly earnings slide to $77.4 million, or $0.11 a share, versus $370.6 million, or $0.54 per share last year. But if you back out an after-tax loss of $0.02 a share for special items, the company's per share number reached $0.13. Revenue for the company dipped 15% to $2.15 billion in the same quarter of 2008.

Looking at Weatherford's performance by region, the company saw its revenues in North America 47% below that of the third quarter of 2008. Perhaps more importantly, operating income generated on our continent was down $280 million from 2008's third quarter. However -- and paying attention to the sequential trend we discussed above -- the quarter's operating income topped those of second quarter by $34 million.

Operations in the Middle East, North Africa, and Asia slipped 6% year over year, and were about flat with the prior quarter. Latin America, however, produced revenues that were 67% higher than the prior year, and up 13% from the prior quarter. Revenues from Europe, West Africa, and the former Soviet Union were about flat year over year, but 11% higher than the previous quarter.

While Weatherford didn't make mincemeat of the second quarter, as CEO Bernard Duroc-Danner noted during the call, "We are more constructive on the prognosis and five quarters ahead through 2010. Pricing is not deteriorating, whether in North America or in international markets." Nevertheless, the company intends to broaden its international exposure next year.

But we'll have to wait until other oilfield service companies such as Schlumberger (NYSE:SLB) and Cameron (NYSE:CAM), along with drillers Diamond Offshore (NYSE:DO), and Transocean (NYSE:RIG) tell us about their quarters for a real handle on the current status of the industry. In the meantime, my feelings are that, with commodity prices headed upward, this sector -- including Weatherford -- might present more opportunities going forward than you realize.

Weatherford has received a full complement of five stars thanks to the outperform calls of more than 800 Motley Fool CAPS players. Why not add your opinion on the company?

Fool contributor David Lee Smith doesn't own shares in any of the companies mentioned. He welcomes your comments. The Fool has a disclosure policy.