Steven Dubner - Freakonomics

So what does an analysis of the ECLS data tell us about school-children’s performance? A number of things. The first one concerns the black-white test score gap.

It has long been observed that black children, even before they set foot in a classroom, underperform their white counterparts. Moreover, black children didn’t measure up even when controlling for a wide array of variables. (To control for a variable is essentially to eliminate its influence, much as one golfer uses a handicap against another. In the case of an academic study such as the ECLS, a researcher might control for any number of disadvantages that one student might carry when measured against the average student.) But this new data set tells a different story. After controlling for just a few variables—

including the income and education level of the child’s parents and the mother’s age at the birth of her first child—the gap between black and white children is virtually eliminated at the time the children enter school.

This is an encouraging finding on two fronts. It means that young black children have continued to make gains relative to their white counterparts. It also means that whatever gap remains can be linked to a handful of readily identifiable factors. The data reveal that black children who perform poorly in school do so not because they are black but because they tend to come from low-income, low-education households. A typical black child and white child from the same socioeconomic background, however, have the same abilities in math and reading upon entering kindergarden.

Great news, right? Well, not so fast. First of all, because the average black child is more likely to come from a low-income, low-education household, the gap is very real: on average, black children still are scoring worse. Worse yet, even when the parents’ income and education are controlled for, the black-white gap reappears within just two years of a child’s entering school. By the end of first grade, a black child is underperforming a statistically equivalent white child.

And the gap steadily grows over the second and third grades.

Why does this happen? That’s a hard, complicated question. But one answer may lie in the fact that the school attended by the typical black child is not the same school attended by the typical white child, and the typical black child goes to a school that is simply…bad. Even fifty years after Brown v. Board, many American schools are virtually segregated. The ECLS project surveyed roughly one thousand schools, taking samples of twenty children from each. In 35 percent of those schools, not a single black child was included in the sample. The typical white child in the ECLS study attends a school that is only 6 percent black; the typical black child, meanwhile, attends a school that is about 60 percent black.

Just how are the black schools bad? Not, interestingly, in the ways that schools are traditionally measured. In terms of class size, teachers’ education, and computer-to-student ratio, the schools attended by blacks and whites are similar.

But the typical black student’s school has a far higher rate of troublesome indicators, such as gang problems, nonstudents loitering in front of the school, and lack of PTA funding. These schools offer an environment that is simply not conducive to learning.

Black students are hardly the only ones who suffer in bad schools. White children in these schools also perform poorly. In fact, there is essentially no black-white test score gap within a bad school in the early years once you control for students’ backgrounds. But all students in a bad school, black and white, do lose ground to students in good schools. Perhaps educators and researchers are wrong to be so hung up on the black-white test score gap; the bad-school/good-school gap may be the more salient issue. Consider this fact: the ECLS data reveal that black students in good schools don’t lose ground to their white counterparts, and black students in good schools outperform whites in poor schools.

So according to these data, a child’s school does seem to have a clear impact on his academic progress. Can the same be said for parenting? Did all those Baby Mozart tapes pay off? What about those marathon readings of Goodnight Moon?

Was the move to the suburbs worthwhile? Do the kids with PTA parents do better than the kids whose parents have never heard of the PTA?

The wide-ranging ECLS data offer a number of compelling correlations between a child’s personal circumstances and his school performance. For instance, once all other factors are controlled for, it is clear that students from rural areas tend to do worse than average. Suburban children, meanwhile, are in the middle of the curve, while urban children tend to score higher than average. (It may be that cities attract a more educated workforce and, therefore, parents with smarter children.) On average, girls test higher than boys, and Asians test higher than whites—although blacks, as we have already established, test similarly to whites from comparable backgrounds and in comparable schools.

Knowing what you now know about regression analysis, conventional wisdom, and the art of parenting, consider the following list of sixteen factors. According to the ECLS data, eight of the factors show a strong correlation—positive or negative—with test scores. The other eight don’t seem to matter. Feel free to guess which are which.

The child has highly educated parents.

The child’s family is intact.

The child’s parents have high socioeconomic status.

The child’s parents recently moved into a better neighborhood.

The child’s mother was thirty or older at the time of her first child’s birth.

The child’s mother didn’t work between birth and kindergarten.

The child had low birthweight.

The child attended Head Start.

The child’s parents speak English in the home.

The child’s parents regularly take him to museums.

The child is adopted.

The child is regularly spanked.

The child’s parents are involved in the PTA.

The child frequently watches television.

The child has many books in his home.

The child’s parents read to him nearly every day.

Here now are the eight factors that are strongly correlated with test scores:

• The child has highly educated parents.

• The child’s parents have high socioeconomic status.

• The child’s mother was thirty or older at the time of her first child’s birth.

• The child had low birthweight.

• The child’s parents speak English in the home.

• The child is adopted.

• The child’s parents are involved in the PTA.

• The child has many books in his home.

And the eight that aren’t:

• The child’s family is intact.

• The child’s parents recently moved into a better neighborhood.

• The child’s mother didn’t work between birth and kindergarten.

• The child attended Head Start.

• The child’s parents regularly take him to museums.

• The child is regularly spanked.

• The child frequently watches television.

• The child’s parents read to him nearly every day.

Now, two by two:

• Matters: The child has highly educated parents.

• Doesn’t: The child’s family is intact.

A child whose parents are highly educated typically does well in school; not much surprise there. A family with a lot of schooling tends to value schooling.

Perhaps more important, parents with higher IQs tend to get more education, and IQ is strongly hereditary. But whether a child’s family is intact doesn’t seem to matter. Just as the earlier-cited studies show that family structure has little impact on a child’s personality, it does not seem to affect his academic abilities either. This is not to say that families ought to go around splitting up willy-nilly.