THE latest decline in the civilian unemployment rate - falling to 7.5 percent in May, from 7.8 percent in March and April - comes as welcome news for the giant US economy. Some 105 million Americans now hold jobs - a remarkable achievement for an economy that has had a massive influx of young people and women into the labor pool during the past decade.
Still, amid all the euphoria surrounding the latest unemployment figures, it is important to keep the employment issue in careful perspective. It is true that unemployment is dropping. Indeed, if the figures go down any further during the next month or so, President Reagan will be able to argue, correctly, that unemployment is lower than when he took office, since the unemployment rate stood at 7.5 percent back in November 1980, when he was elected.
What also needs to be noted, however, is that too many Americans - 8.51 million of them - continue to be without jobs. Many of the unemployed are highly skilled workers. And unemployment among blacks and youths, particularly minority youths, remains high. In addition, hundreds of thousands of discouraged workers have virtually dropped out of the labor market altogether and are no longer even counted in official statistics.
To note all this is not to detract from the latest decline in joblessness. But it is to recognize some underlying characteristics about the US economy:
* Its long-range growth continues to be found in the services-electronics-small business sectors. Unemployment remains a special problem in older manufacturing industries.
* Unemployment continues to be most pronounced in certain geographical sections of the United States, such as the upper Midwest and the Pacific Northwest.
Policies need to be adopted to rectify the employment/unemployment imbalance now arising because of deep-seated structural changes occurring within the economy, such as the downsizing of older manufacturing industries. No person, or region of the nation, should be permanently left out of the recovery. That means the need for a greater emphasis on job training and retraining, and perhaps such other steps as development of new tax incentives to encourage businesses to be established in areas of high unemployment.
Most economists believe the expected slowdown in the US economy may at last be under way - although the recovery is continuing. That slowing is to the good, if it means a steadier rate of growth. But one result may be a slowing in the rate of growth in employment. Data Resources Inc., for example, believes that the jobless rate will hover around 7.5 percent next year, and even rise slightly , to around 7.6 percent, in 1986, as more young people and women come into the labor market.
With foresight, such a stagnation in the jobless rate - in the 7.5 percent range - need not come about. At the same time, government officials and private economists need to rethink what constitutes ''full employment'' in today's economic setting, with so many women, young people, and even ''outsiders,'' such as illegal aliens, holding down jobs. Surely, one key objective of the new White House and Congress next year must be ensuring that all Americans able and willing to work can find jobs.