Those arguments may be heard repeatedly this week, as the Senate begins debating the jobs bill. The full bill — a mix of tax cuts, public works, unemployment benefits and other items, costing $447 billion — is unlikely to pass, but individual parts seem to have a significant chance.

The full 9.8 percent drop in income from the start of the recession to this June — the most recent month in the study — appears to be the largest in several decades, according to other Census Bureau data. Gordon W. Green Jr., who wrote the report with John F. Coder, called the decline “a significant reduction in the American standard of living.”

That reduction occurred even though the unemployment rate fell slightly, to 9.2 percent in June compared with 9.5 percent two years earlier. Two main forces appear to have held down pay: the number of people outside the labor force — neither working nor looking for work — has risen; and the hourly pay of employed people has failed to keep pace with inflation, as the prices of oil products and many foods have jumped.

During the recession itself, by contrast, wage gains outpaced inflation.

One reason pay has stagnated is that many people who lost their jobs in the recession — and remained out of work for months — have taken pay cuts in order to be hired again. In a separate study, Henry S. Farber, an economics professor at Princeton, found that people who lost jobs in the recession and later found work again made an average of 17.5 percent less than they had in their old jobs.

“As a labor economist, I do not think the recession has ended,” Mr. Farber said. “Job losers are having more trouble than ever before finding full-time jobs.”