True or false: Workers over age 65 are less productive, more often absent from the job and cost companies more due to their higher salaries and medical benefits?

All false, according to four major corporations which have considerable experience dealing with elderly employes. The four -- Xerox, Polaroid, Atlantic Richfield and Bankers Life and Casualty -- testified yesterday before a Senate Special Committee on Aging's hearing on ways to encourage work after 65.

Sen. Charles H. Percy (R-Ill.), who was a corporate chairman before becoming a legislator, outlined what he termed the "obvious contradiction" in our society today.

"Inflation," he said, "is having a serious impact on the elderly. Still, the evidence suggests that people are opting for early retirement despite the economic problems it may bring."

He noted that a recent change in the law raising the mandatory retirement age from 65 to 70 has had little effect on the number of older workers, although individual companies like Polaroid report that as many as 80 percent of their employes over 65 are still on the job.

Early retirement for some has become a part of the American dream. A survey conducted last fall by the President's Commission on Pension Policy shows that 47.5 percent of the population expect to retire at age 62 or before, even though 63 percent said their retirement income would be inadequate.

C. Peter McColough, the commission's chairman, said there is a "fairly general experience" in the business community today that inflation is causing people to work longer. But fundamental changes like tax credits, alternative work patterns such as phased retirement, and educational and vocational training are needed to solve the "basic attitudinal problem" of opposition to work after 65, he said.

This has become a national necessity because the number of young workers is shrinking in comparison to the number of older ones, as are the payroll taxes to pay for their retirement, McColough added.

Xerox, which McColough also heads, has developed a preretirement counseling program, although as a fairly young company it has few older workers.

Bankers Life and Casualty of Chicago, on the other hand, has had 40 years experience with older workers. Gerald L. Maguire, vice president of corporate services, tried to puncture some of the myths that he claimed scare employers most.

Retirees do three times as well as commercial temporary employes who do not know the business, Maguire said. "Older workers are a special bred of people, self-disciplined. They know themselves when it's time to go; in 40 years we've never had to tell a person to retire."

He contended it is more economical for a company to continue paying older workers' higher salaries than to retrain new employes. The old take only 20 to 33 percent of the compensatory time taken by the young for accidents, and insurance is cheaper because of Medicare, Maguire said.

Polaroid has several innovative work patterns, including tapering off and "rehearsal retirements." The latter allows an employe to take off three to six months without pay just to see how it feels to retire. If dissatisfied, the employe can return to his or her previous job.

Atlantic Richfield, the only blue-collar company represented at yesterday's hearing, has only two years experience without a mandatory retirement age. Harold S. Page, vice president for personnel, said just 3 percent of employes reaching 65 elected to stay, whereas 80 percent continued to retire early.

Page admitted it will be difficult to convince labor unions and management of the advantages of post-65 work. Moreover, he warned that if industry doesn't expand in the 1990s there may be serious problems with workers in the 25-to-45 year bracket whoe feel older workers are delaying their promotions.

Sen. John Glenn (D-Ohio) asked the corporate executives their opinion of a test being developed by the National Institutes of Health to assess skills to "find out how old is old." The executives declared themselves unanimously against such an idea.