Job growth slowed in January, offering a tentative sign that the economy might be shifting down a notch from its unexpectedly robust pace at the end of last year.

According to a Department of Labor report released Friday, employers across the nation added 111,000 jobs last month, about half the monthly gains recorded at the end of last year and less than most Wall Street economists expected.

Unemployment rose a tenth of a percentage point, to 4.6 percent, the highest level since September, because of a substantial increase in the number of people entering the labor force seeking jobs.

The weaker data for January soothed some investors in financial markets, who have been worrying that faster job and wage growth could feed through to higher inflation. "We're looking at the ultimate rosy scenario," said Robert S. Gay, managing partner of financial consulting firm Fenwick Advisors. "Not too fast, not too slow."

But employers might be hiring at a faster clip than is immediately apparent. The Labor Department acknowledged that employers added nearly 1 million more jobs from March 2005 through December than it had previously estimated.

Last year, employment growth exceeded earlier estimates by more than 400,000 jobs. The magnitude of the change suggested that the Labor Department might be seriously underestimating employment growth.

"The size of the upward revisions were enormous," said Joshua Shapiro, chief U.S. economist with MFR. "You put the pieces of the puzzle together, and it sort of tells you that the 111,000 number is not something to focus on." January's number will be revised in February and March, and will be subject to an annual adjustment next year.

The reported changes to prior data were mostly because of the annual adjustment of the sample of businesses that the Labor Department surveys to put together its employment figures. The department also recalibrated its model of the birth and death of businesses -- which feeds into its estimates of employment growth.

The adjustments fit an underlying picture of an economy that is somewhat stronger than previously thought, despite the continuing weakness in the housing market -- which has affected employment in the housing sector. Early estimates put growth in the fourth quarter at 3.5 percent, faster than expected.

Indeed, the University of Michigan's consumer confidence gauge for January, which was released Friday, rebounded to its highest level in two years, as cheaper energy encouraged expectations of a stronger economy, better jobs and higher wages.

Richard T. Curtin, who heads the university's surveys of consumers, noted that in January only 27 percent of consumers said they expected unemployment to rise over the next year, the lowest percentage in two years, down from 41 percent in the August survey. "Consumers expect a big increase in real incomes," Curtin added.

Wages did not grow much in January. Hourly wages increased 3 cents, or 0.2 percent, before inflation, the slowest since September. The total hours worked in the private sector declined to 33.8 a week, from 33.9 in December.

Though inflation in January has not yet been reported, it would not be surprising if it were to exceed the growth in hourly wages.

When the Federal Reserve voted Wednesday to leave interest rates unchanged, it sounded its usual cautionary note about inflation. But this time, it was more optimistic that prices would "moderate over time," its statement said.

Still, some economists remain nervous about wage growth. "Increases in wages should not necessarily lead to wage inflation of the sort that would worry the Fed if we continue to see productivity growth. But productivity growth has been slowing," said Bernard Baumohl, managing director of the Economic Outlook Group.

Even so, Baumohl said, the Fed might find it difficult to raise interest rates just as workers are starting to see real wage gains. "It's taken so long for workers to catch up that you really don't want to terminate that abrupt increase in income. The Fed is going to have to be very careful here."