The firm's UK Search Engine Performance Report: Q1 2009 showed that advertisers have improved their ROI by 25% over the first three months of the year, even though they have cut spend by 10.5% since the last quarter of 2008.
The report also revealed that paid-for search spend decreased by 6% year on year.
The paid-for search marketing specialist compared data on the first quarter of 2009 with the same period last year, using a sample of advertisers from sectors including financial services, travel, entertainment, retail and telecommunications.
David Karnstedt, Efficient Frontier's president and chief executive, said: "We believe that ROI will continue to be a priority for advertisers as they seek greater efficiencies in keyword marketplaces.
"This trend, coupled with increased search volume, represents a significant opportunity for advertisers to gain market share in key categories and obtain additional, valuable traffic at a discounted price point."
The report was based on an analysis of 7bn impressions and 114m clicks across a number of Efficient Frontier's clients.
Efficient Frontier manages more than $750m of search marketing spend annually.