Christopher Jencks and Meredith Phillips, co-editors of the book The Black-White Test Score Gap, discuss why the gap persists and what can be done to close it.

African Americans score lower than European Americans on vocabulary, reading, and math 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. It has narrowed since 1970, but the typical American black still scores below 75 percent of American whites on almost every standardized test.¹ This statistic does not imply, of course, that all blacks score below all whites. There is a lot of overlap between the two groups. Nonetheless, the test score gap is large enough to have important social and economic consequences.

Closing the black-white test score gap would probably do more to promote racial equality in the United States than any other strategy now under serious consideration. Eliminating the test score gap would sharply increase black college graduate rates. It would also reduce racial disparities in men's earnings and would probably eliminate racial disparities in women's earnings. Eliminating the test score gap would also allow selective colleges, professional schools, and employers to phase out the racial preferences that have caused so much political trouble over the past generation.

Narrowing the test score gap would require continuous effort by both blacks and whites, and it would probably take more than one generation. But we think it can be done.

The results from a Tennessee class size experiment indicate, for example, that cutting class size in the early grades raises both black and white children's test scores but raises black children's scores more. Historical evidence also seems to support the hypothesis that lowering class size helps narrow the black-white test score gap. When low birth rates reduced school enrollment in the 1970s, the teacher-pupil ratio rose and classes shrank. Independent analyses by Ron Ferguson and David Grissmer suggest that this class size reduction was followed by a marked decline in the black-white test score gap.

Although measuring teachers' competence is harder than counting the number of children in a classroom, teachers' test scores show a stronger association with how much students learn than any other widely used measure. Screening teachers for verbal and mathematical competence is thus likely to boost children's performance. Since the teachers who fail competency tests are concentrated in black schools, such exams would probably prove especially beneficial to black students, although this benefit may be partially offset by the fact that the teachers who fail such tests are also disproportionately black.

Ferguson's review of the literature on teachers' expectations concludes that teachers do have lower expectations for blacks than for whites, but that this is largely because blacks enter school with weaker cognitive skills than whites and learn a bit less after entering. Ferguson also finds some evidence that low teacher expectations have a more negative effect on black children than on their white classmates.

Although we believe that improving the nation's schools would help reduce the black-white test score gap, schools alone cannot eliminate the gap. The typical black four-year-old's vocabulary score falls below the twentieth percentile of the national distribution. Relying entirely on educational reform to move such a child up to the fiftieth percentile does not strike us as realistic. If we want equal outcomes among twelfth graders, we will also have to narrow the skill gap between black and white children before they enter school. There are two ways to do this: change black children's preschool experiences and change their home experiences.

A review of research on preschool effects by Steven Barnett, a professor of education at Rutgers, strongly suggests that cognitively-oriented preschool programs can improve black children's achievement scores, even though the benefits fade somewhat as children age. Because black preschoolers are concentrated in Head Start centers, getting Head Start to emphasize cognitive development should be a high priority.

Parenting practices almost certainly have more impact on children's cognitive development than preschool practices. But getting parents to change their habits is even harder than getting teachers to change. Like teachers, parents are usually suspicious of unsolicited advice about how to deal with their children. But once parents become convinced that a particular practice really helps their children, many adopt it. As a practical political matter, whites cannot tell black parents to change their parenting practices without provoking charges of ethnocentrism, racism, and much else. But black parents are hardly the only ones who need help. We should be promoting better parenting practices for all parents using every tool at our disposal, from preschool outreach programs and home visits by nurses to television programs, or anything else that looks promising.