For years many older workers and some organizations of the elderly have railed against limits on how much a Social Security beneficiary can earn from a job without a reduction in benefits.

Critics contend that the ceiling on earnings, which is actually a test of whether a person is retired and should receive retirement benefits, unfairly forces workers to retire when they prefer to keep working and need the money. The critics claim that millions of workers are ready, willing and able to continue full-time work if the earnings limit is lifted.

"Because of the earnings test, seniors are being forced out of the work force and into the rocking chair," Rep. J. Dennis Hastert (R-Ill.) said recently. "All because of a Depression-era fossil no one has the courage to change."

Now, however, the latest issue of the Social Security Bulletin looks at all the studies and experiments to date and concludes that the notion of many millions of Americans waiting to work is a fantasy.

"Virtually all this research indicates that . . . eliminating the test would have a minor impact on the work activity of older Americans," writes Michael V. Leonesio of the divison of economic research of the Social Security Administration.

Under the law, a worker age 65 through 69 can earn $9,360 a year from a job without losing benefits. For earnings above that, benefits are cut $1 for each $3 earned. For persons 62 through 64, the limit is lower, and there is no limit once a person reaches his or her 70th birthday. Income such as dividends and interest is not counted as part of earnings. About 750,000 affected people now earn more than the current limits.

Leonesio said various studies suggest that factors other than the earnings test are far more important in a person's decision about whether to retire.

These include whether the person has a liberal private pension and fairly high Social Security benefits, his or her health and physical capacity to continue working, job opportunities at a given moment, and whether it is necessary to stay home to care for an ill spouse.

And there are ways to mitigate the law's impact. For example, if a person chooses to work past 65, he or she can delay receipt of benefits and get a special permanent increase in benefits when they begin.

Moreover, if a beneficiary works and loses some benefits as a result, part of them may be recouped later because the added years of work may improve the basic earnings history on which subsequent benefits are recomputed.

"In sum, arguments that the retirement test substantially deters work by older persons are unsuppported by credible evidence," Leonesio said.

The new report could influence an existing congressional dispute over the earnings limit. Senate Minority Leader Robert J. Dole (R-Kan.) and other Republican congressional leaders earlier this year held a news conference to press for repeal of the earnings limit, which would cost $25 billion over the next five years.

In the Senate, a more modest provision has been approved, based on a proposal by Sen. Lloyd Bentsen (D-Tex.), to raise the 65-69 earnings limit this year to $10,560.

In the House, a Ways and Means subcommittee has endorsed a smaller increase, to $10,200 next year.

Although Social Security Commissioner Gwendolyn S. King favors some liberalization of the earnings test, she said, "Any responsible change in the earnings test must recognize the seriousness of the current budget deficit and be structured in such a manner as to be revenue neutral and not jeopardize the long-term financial solvency of the Social Security program."