Beginning in the mid-1990's, pay increases for most workers slowly but steadily outpaced the rate of inflation, improving the living standards for nearly all Americans. But an unexpected reversal last year in those gains has set off a vigorous debate among economists over whether the decline is just a temporary dip or portends a deeper shift that may cause the pay of average Americans to lag for years to come.

Even though the economy added 2.2 million jobs in 2004 and produced strong growth in corporate profits, wages for the average worker fell for the year, after adjusting for inflation - the first such drop in nearly a decade.

"Pay increases are not rebounding, even though the factors normally associated with higher pay have rebounded," said Peter LeBlanc of Sibson Consulting, a division of Segal, a human resources consulting firm.

The problem is not with the jobs themselves. Most economists dismiss as overblown the widespread fear that the number of jobs will shrink in the United States because of foreign competition from China, India and other developing nations. But at the same time many of these economists argue that the increasing exposure of the American economy to globalization, along with other forces - including soaring health insurance costs that leave less money for raises - is putting pressure on wages that could leave millions of workers worse off.