David Boldt / Alarms and Diversions

The sensitive subject of the differences in black and white test scores is about to make a reappearance in the public arena -- pushed forward this time by, of all people, liberals.

The subject was shoved aside for the most part after the intense flare-up of controversy following the publication in 1994 of The Bell Curve by Charles Murray and Richard Herrnstein, who attributed the gap largely to inherent differences between blacks and whites.

It will be brought back by The Black-White Test Score Gap, edited by Christopher Jencks of Harvard and Meredith Phillips of UCLA, and published this month by the Brookings Institution. A synopsis appears in the current issue of The American Prospect, a liberal journal.

The Jencks book is intended to be a rebuttal to The Bell Curve but, ironically, may accomplish something Murray hoped his book would do, yet did not.

That is, the Jencks book may succeed in bringing the subject of the test-score disparity out into the open; provide a vocabulary with which it can be discussed civilly; and open the way to formulate constructive social policies.

The Bell Curve, by contrast, zoomed through public policy debate like a Stealth bomber. Its name was seldom, if ever, spoken aloud in legislative or judicial debate, though its effects were clearly felt. Affirmative-action policies that had been sacrosanct for years were suddenly wobbling.

One can, if one wishes, go down for the third time in a stormy debate over the degree to which Jencks, Phillips and the two dozen other contributors have succeeded in their goal of showing that The Bell Curve overstates the role of innate intelligence and understates the importance of social environment.

What might be more useful, however, would be to use the conclusions drawn by Jencks and Phillips in their introductory summation as representing a more or less universally accepted baseline of conclusions about the test-score debate -- and to use that as a starting point for policy discussions.

Without attributing the differences to genetics, Jencks and Phillips make clear that the present gap is large and important. Blacks score lower than whites on vocabulary, reading and mathematics tests, as well as on tests that claim to measure scholastic aptitude and intelligence.

"The gap appears before children enter kindergarten, and it persists into adulthood," they write. "It has narrowed since 1970, but the typical American black still scores below 75 percent of American whites."

This gap is not the result of cultural bias in the tests, they conclude, and equalizing the social and economic background of blacks and whites would have only a small effect. Moreover, the tests do measure skills that matter in the real world.

The editors believe that the gap can be greatly reduced or even eliminated. To demonstrate that test scores are subject to change, they point to the fact that IQ scores generally have generally been rising, that the gap between blacks and whites had been narrowing until very recently, and that black children adopted by white parents post higher test scores, at least until adolescence.

(The drop-off in the scores of adopted black children when they become teenagers could be the result of negative pressures from other black teenagers, though the power of these peer pressures is left unresolved in the book.)

The precise causes for the current differences between blacks and whites aren't known, Jencks and Phillips acknowledge, largely because the subject has been seen by researchers as too hot to handle -- a state of affairs that will have to change, they say.

Their "best guess" is that new theories will emerge based less on families' economic and educational resources, and more on "the way family members and friends interact with one another and the outside world."

Parenting styles and analyses of subtle aspects of school environment, such as the expectations of teachers, will probably turn out to have larger effects than can now be proved, they hypothesize.

Some factors that are known, but haven't been acted on, can be put to better use, they say. For instance, it's known that one of the most important things is to have teachers who themselves have posted high scores in achievement and aptitude tests, yet too little is being done to attract such people into teaching.

Interestingly, the conclusions in the book are largely congruent with the attitudes of black parents reported in a recent Public Agenda study, A Time to Move On. It showed that far more black parents believed that standardized tests "measure real differences in educational achievement" than believed the tests were culturally biased.

An overwhelming majority of black parents (78 percent) would like to see the test-score disparity highlighted, rather than covered up, believing this will justify the need to improve educational opportunities for blacks.

The black parents also want the best possible teachers hired, regardless of race, and higher standards in the schools their children attend, things Jencks and Phillips can buy into -- as well as Murray.

No one, after all, would dispute the concluding line of Jencks and Phillips' introduction: "We can do better."