IN JULY, Prince George's County School Superintendent John Murphy released a study showing that black children in that jurisdiction were scoring more than 20 percentile points behind their classmates on standardized tests. It was the first publication of such figures in Prince George's, where enrollment is now 57 percent black, the highest percentage in any suburb in the area. Mr. Murphy said the study, which he had commissioned, was proof of "a serious problem" that has "got to be addressed."

Three weeks later, the Alexandria school system, the other suburb with a sizable black enrollment (47 percent) published similar statistics, also for the first time. There have since been news stories about the other suburban jurisdictions. They have been releasing the results of their much smaller black enrollments for a number of years. They, too, show large disparities in average scores between whites and blacks.

In one sense statistics such as these have long since ceased to be news, or at least to be a surprise. But in both Prince George's and Alexandria there had been a reluctance to release test scores by race in the past, partly for fear they would be misinterpreted. School officials thought dissemination of the results might be taken as racist and might also do a disservice to blacks. Yet as Mr. Murphy and Alexandria Superintendent Robert Peebles correctly perceived, the opposite is true. The test scores do not measure racial characteristics. Nor do they necessarily measure the quality of schools. They are reflections mainly of socio- economic history -- and they are mirrors of need. They represent powerful claims against the resources of the school systems involved. The hardest work in America may be raising the test scores of schoolchildren from disadvantaged homes. But progress is possible. In the District of Columbia public schools, an effective superintendent, a combination of public and private support and a tightly focused curriculum have lifted scores in the last several years, so that younger students now perform above national norms. There have been improvements in Arlington County as well. Within the last four years, for example, while scores of white students have remained fairly stable, scores of black eighth-graders have risen from the 30th to the 40th percentile in reading, and from the 52nd percentile to the 60th in math. County officials attribute this largely to a new remedial program put in place in schools of greatest need.

Particularly in suburban settings, the politics of remedial efforts can be as difficult as their execution. School budgets tend to be zero-sum games; if one program gains, as often as not another must lose. There is also no guarantee that more resources -- more money -- will bring about test- score improvements. Quite the contrary. The money has to be in sufficient concentrations to do some good, and even then it must be artfully spent. Mass education is a chancy business. But too much is at stake not to try. The Prince George's and Alexandria superintendents, in laying out the dimensions of the problem, have challenged both the communities they serve -- including the black communities -- and the principals and teachers they employ. The same challenge is out in the other suburban jurisdictions. That is finally what the new test scores mean.