IT WAS only 10 years ago that newspapers and magazines were full of stories of an impending national shortage of doctors. A few years before that, the medical profession was ridden with fear that it was turning out too many researhers and not enough doctors interested in taking care of sixk people.

Well, the system went to work with federal payments to medical schools, grants to universities that built new schools, curriculum changes, accelerated training of "non-physician health care providers" (meaning nurse practitioners, physician assistants and nurse mid-wives) and other initiatives. Now the news is that the country faces a large surplus of doctors, while the medical profession is worried about a shortage of medically trained researchers.

According to a recent report by an advisory committee to the Department of Health and Human Services, there will be a 15 percent oversupply of physicians by 1990, which will balloon to about 30 percent by 2000. And according to the report, it is already too late to correct the 1990 surplus.

This surplus is of concern because the government believes that due to the astronomial costs of training doctors, the effects of health insurance and a variety of other factors, the existence of too many physicians will raise, not lower, health care costs.

At the same time, yet another report to the president concludes that the country is facing severe shortages of engineers and some types of scientists, in particular computer scientists. It wasn't too many years ago that science PhDs were finding it so hard to get jobs in their fields that college deans were likening the situation to the years of the Great Depression. This report also concludes that just two decades after the sweeping post-Sputnik curriculum reforms the country as a whole is heading toward "virtual scientific and technological illiteracy." The report's authors believe that the manpower shortages can be corrected but that the innovative capacity of American industry will be severly hampered in the interim."

Assuming that both reports are generally acccurate, in their predictions, both raise serious problems that can and should be corrected. But the more interesting question is why the country is still so unable to predict and adjust its supply of doctors, scientists, engineers and comparable professionals. The pendulum seems to swing between the extremes of surplus and shortage. Considering how long it takes to train these individuals and, therefore, how long it takes to correct an imbalance, it should be possible -- and it clearly is necessary -- to do much better.