Facebook has launched a new conversion measurement optimization system for direct response marketers to help them measure the ROI of their Facebook ads by counting “relevant” user actions, like registrations and shopping cart checkouts. The system can be used with all Facebook ads and sponsored stories, and in combination with any targeting.

“Marketers can now also use optimized CPM (OCPM) to deliver ads to people who are most likely to convert on their websites,” Facebook says in a blog post. “Beta tests have shown that when conversion measurement is used with optimized CPM, ads reduced the cost per conversion by 40 percent when compared to CPC ads using the same budget.”

“This means that marketers who are interested in using Facebook ads and sponsored stories to drive specific actions on their websites can now use conversion measurement both to understand the ROI of their ad spend and to improve that ROI on future campaigns,” the company adds. “This should be extremely valuable for marketers in e-commerce, retail, travel, financial services, and other direct-response industries that value actions taken on their websites. Early testing of conversion measurement with optimized CPM has generated strong results for multiple advertisers who are focused on driving user actions on their websites.”

Specifically, Fab.com used Facebook’s conversion measurement and optimization to reduce its cost per new customer acquisition by 39%, according to Facebook. The company also says the Democratic Governors Association used the system to decrease its cost per conversion by 85% compared to any other campaign it had run online.

Facebook notes that conversion measurement is the only solution that can report when a user views an ad on one device and converts on another.

Facebook’s conversion measurement can be used in Power Editor, the Ads Manager and by API partners. Facebook provides step-by-step instructions here.