The College Entrance Examination Board has handed black America a public relations dilemma. It has revealed that (1) blacks average 110 points behind whites on their College Board scores -- a significant gap, considering that the range is only from 200 to 800 -- and (2) that black scores are improving at a significantly faster pace than white scores.

Either piece of information taken alone would be a PR snap. Blacks lag behind whites in the Scholastic Aptitude Test (SAT)? Well of course. The tests are culturally biased, and besides they don't measure anything worth measuring. The only reasonable thing to do is to abandon the whole testing enterprise and find other ways to screen college applicants.

Blacks are gaining faster than whites? Of course. It only proves the effectiveness of such efforts as school desegregation, affirmative action and compensatory educational programs. It also shows you what can happen when black superintendents take over more of the big-city school systems.

Public relations aside, what do the two sets of figures demonstrate? Not even the people who run the College Board are sure.

It seems reasonable to assume that the test scores reflect something real, whether that something is academic improvement or economic improvement or, most likely, the two things working together and influencing each other.

Thus, it makes sense that black scores would be rising during a period when more and more blacks are entering the cultural and economic mainstream. And it makes sense that a considerable gap would remain in view of the fact that the income gap between blacks and whites is still very large.

For instance, two-thirds of the black and Puerto Rican students who took the College Boards came from families whose annual income was under $12,000. Less than a quarter of the whites who took the tests were from families that poor. Asian-Americans, who outscored whites on the SAT, had a smaller percentage of families than whites in the under-$12,000 category.

But that isn't all of it. Neither income nor cultural bias explains why Puerto Ricans outscored blacks on the verbal portion of the test -- a median score of 361 for Puerto Ricans and 332 for blacks. (The white verbal median was 442.)

Can part of the explanation be that Puerto Ricans are concentrated in sophisticated New York City, with relatively few of them in the rural areas that tend to produce lower academic scores? Then why did both American Indians (391) and Mexican-Americans (373) outscore both blacks and Puerto Ricans?

Ann Cleary, director of evaluation services at the University of Iowa, offers an explanation that covers a number of factors: "As young children, the poorer students are not getting as stimulating an environment as more educated parents are apt to provide," she said. "And more of the black youngsters are living in single- parent homes, where they may not be getting as much attention."

The full answer may never be known. But it does strike me as unmitigated good news that the white- black gap is closing, at a time when the scores for whites also are climbing, after a steady decline since 1963.

Surely the black gains must demonstrate improved economic and educational opportunity has a payoff in academic achievement. And if that is so, the implications for social policy are obvious.