Christina Romer used her final speech as chair of the White House Council of Economic Advisors to stress her pride in Obama's policies targeting a "terrifying recession."

"The president took office in the midst of a recession of historic proportions, but for which history provided little guidance," she said.

Framing a debate that is likely to be central in upcoming mid-term elections, Romer maintained that Obama's "unprecedented, pragmatic policy actions have made an enormous difference," while admitting the impact of 787-billion dollars of spending is not always easily seen.

"Because the final bill was a mixture of hundreds of measures, many of which don't come with Recovery Act signs or easily identifiable links to the act, it has been hard for people to see what the act has done."

Romer's tenure has been marked by economic turmoil, as Obama's administration was buffeted by low growth, high unemployment and fierce criticism of massive government stimulus spending.

But amid ferocious Republican opposition to more spending that would swell the US budget deficit, Romer backed further measures.

"Concern about the deficit cannot be an excuse for leaving unemployed workers to suffer," she said.

Romer is expected to remain in office until September 3, when she plans to resume duties as a professor of economics at the University of California, Berkeley.

She is tipped as a possible candidate to take over the reins of the San Francisco Federal Reserve.