An article Tuesday incorrectly reported change in the number of physicians willing to accept Medicare payments as payments in full. The figure declined from 60.8 percent in 1970 to 50.5 percent in 1976, but since then it has increased, to 53 percent in 1982.

Officials of the Health and Human Services Department's Health Care Financing Administration have been trying to figure out how to get more doctors to accept the standard government reimbursement as full payment for treating Medicare patients.

Doctors with Medicare patients can choose, patient by patient, how to get paid. They can "accept assignment"--that is, accept the standard Medicare fee as payment in full--or they can bill the patient, usually for more.

The patient then must pay the doctor directly and seek reimbursement from Medicare and his own health insurance plan, if he has one. The reimbursement is often less than the doctor's bill.

Government health officials say the percentage of doctors willing to accept "assigned" payments has been decreasing steadily. Ten years ago, doctors accepted assignment for 60 percent of all Medicare claims. Today, the figure is 50 percent.

One suggestion for raising that percentage is to force them to choose one payment method for all their Medicare patients. The National Commission on Social Security Reform has recommended that doctors be required to decide each year whether to get in or out of the program.

The HCFA had the Center for Health Economics Research in Boston study the probable outcome of such a requirement. It predicted that the assignment rate would fall another 10 percent, forcing more older patients to pay more.

Which doctors generally accept assignment? Studies show that they are usually general practitioners and family doctors, who generally charge lower fees. They also are likely to be taking care of poor patients who have no prospect of coming up with more cash. Those who most often reject the standard reimbursement are specialists and other doctors who can command higher fees. FIXED PRICE FOR CARE . . . There is competition now in selling health care in most cities. With federal encouragement, scores of medical groups are offering most of the medical and hospital care an individual or family needs for a fixed price per month.

The idea is that these plans will avoid hospitalizing their subscribers unnecessarily, so they can end their year with a profit--and help keep the nation's health-care costs down. And by federal law, large employers must offer their employes a choice of traditional health insurance and membership in a fixed-price plan.

HHS officials are finding that the jury is still out on whether the new plans will save money in the long run. Arthur D. Little Inc. made a computer analysis for the HCFA of employe benefit plans at the American Can Co., at General Mills in Minneapolis, at a third, unidentified company, in a Teamsters' pension fund in Houston and in the Mendocino County, Calif., school system.

According to Health Policy Week, the study found that the fixed-price plans seemed cost-effective for their subscribers. But the sicker employes have been sticking with or shifting into traditional fee-for-service insurance plans. The outcome might be to make these plans more expensive. ONWARD AND UPWARD . . . Artificial-kidney machines, heart-lung machines, heart pacemakers, radioisotopes--the list of new medical technologies grows ever longer and more expensive. Technology, it is often said, is one of the main forces driving health costs upward and HHS up the wall.

But a recent publication of the American Enterprise Institute for Public Policy Research warns against pinning the responsiblity on technology alone.

It says the increase also reflects the nation's progress in covering the costs of illness with health insurance, including Blue Cross, Blue Shield, private carriers and Medicare and Medicaid.

Medical research and medical insurance are intertwined in a steep upward cost spiral, said Burton Weisbrod, professor of economics at the University of Wisconsin, in "Economics and Medical Research."

The federal government, through HHS, is playing a clear role, he said: financing most of the country's medical research, then having to provide a large share of the payments for the new treatments that research produces.