Washington — A major Pentagon study of its new recruits presents military planners with mixed news about how well the all-volunteer force is working.
In general, those who join the armed services score a bit higher than the national average on qualification tests measuring ''trainability.'' But minorities -- who make up a disproportionately high percentage of the military -- score significantly lower than whites.
These results have added fuel to the debate about those who provide the nation's defense. Are the tests racially biased, as some minority groups are charging? What do the test scores say about the level of education in predominately nonwhite public schools? Is the all-volunteer concept moving the country toward a military that is increasingly less representative of the general population?
Over the short range, military recruiting and retention has brought good news to the Pentagon. Last year, for the first time since conscription ended in 1973, all four service branches met their recruiting goals, with the highest percentage of high school graduates (83 percent) in Defense Department history.
Test results released this week show 1981 recruits scored 52 on average in the military's Armed Forces Qualification Test (AFQT), compared with 51 for the general youth population. This would seem to rebut critics who say the military has been drawing less capable persons since the draft ended.
Within these general results are more interesting figures. While white recruits score a bit below the general white population, black and Hispanic recruits score significantly above the general black and Hispanic populations. Nonwhite recruits are also much more apt to have a high school diploma than non-whites generally. In the civilian population, whites are more apt to have graduated from high school than nonwhites, but in the military the reverse is true.
Still, the average test score differences between whites and nonwhites are distinct: 58 for white recruits, 33 for blacks, and 41 for Hispanics.
The Pentagon is playing down these differences. In a statement released with the ''Profile of American Youth'' study, the Defense Department said, ''No inferences whatsoever regarding the intellectual abilities of any group should be drawn from this study. The study merely indicates the capacity of individuals to be trained for duties in the Armed Services and was not done to make any judgments about subpopulations.''
Inferences about this testing of nearly 12,000 young men and women are being drawn in other quarters, however.
''1981 was obviously a very good year, and if they want to hang their hat on it, that's fine,'' said Charles Moskos, a Northwestern University sociologist who has done considerable research and writing on military manpower issues. But ''you really have to look at the long-term trends since the end of the draft,'' he adds.
Dr. Moskos finds particularly troubling certain trends in the Army. During the last peacetime draft year (1964), 37 percent of all Army recruits scored above average on the AFQT. Since the end of the draft, scoring in the upper categories has averaged 19 percent (23 percent in 1981). Over the same period, the number of recruits with some college experience has dropped sharply, and the percentage of blacks in the army has risen from 12 percent to 33 percent.
Congressional defense analysts are concerned with several military manpower issues: the degree to which the recession may be temporarily relieving recruitment and retention problems, the high percentage of non-whites and relatively lower income whites, the longer-range trends in recruit capabilities as reflected in test scores, and the fact that the ''youth cohort'' -- the number of eligible males reaching age 18 -- will drop 24 percent during the 1980 s, just when the Reagan administration wants to add about a quarter of a million people to the armed forces.
In 1979, the Pentagon discovered that since 1976 it had been miscalibrating its AFQT test scores. This meant that, in fact, the military had been recruiting fewer people in the average and above average test categories and more in the below average categories.
As a result, Congress (over Defense Department objections) set limits on the number of non-high-school graduates (35 percent) and below average test-takers ( 25 percent) that could be inducted. These limits will become even stiffer next year.
This in effect has helped the military attract ''smarter'' people at a time when the economy is boosting the effects of a major recruiting campaign and military pay raise.