The report by the nonpartisan Congressional Budget Office still paints a bleak financial picture for the future of the retirement system, which faces significant strain as the aging baby boom generation retires.
The bipartisan trustees who oversee Social Security predicted in March that the system's shortfall would be 1.89 percent of taxable payroll, or about $3.7 trillion.
But using rosier economic assumptions over the next 75 years on such things as inflation and productivity, congressional budget forecasters said the shortfall would be 1 percent of taxable payroll.
The report comes as debate continues over what to do about the shortfall. Cutting benefits or raising taxes are the most common suggestions, reports CBS News Correspondent Bob Fuss, though President Bush favors partially privatizing the system by letting people directly invest some of their Social Security taxes.
"While the differences in the estimates should be fully studied by economists and actuaries, they are not an excuse to delay strengthening Social Security," said Sen. Lindsey Graham, R-S.C., who has introduced legislation to overhaul Social Security to let younger workers invest some of their payroll taxes in the stock market through personal accounts.
"Even with the more optimistic assumptions used by the CBO, the long term deficits facing Social Security do not go away," he said.
But opponents of plans to partially privatize Social Security say the new report raises questions about the severity of system's finances.
"The CBO report shows just how tentative estimates about the problems of Social Security are, and how absurd it would be for policy-makers to dramatically alter the program based on those numbers," said Barbara Kennelly, president of the National Committee to Preserve Social Security and Medicare.
Both reports pegged 2019 as the year the system will start paying out more in benefits than it takes in payroll taxes.
Analysts say that date is likely more significant because the insolvency projections count on funds owed the system by the government in the so-called trust fund. Those funds, however, already been spent and must be repaid.