This has forced states, many of which had no data on the achievement of poor or black children, to intervene to ensure that schools and school districts find ways of raising the achievement of children who previously fell through the cracks. But schools and school districts are often not equipped to do, or even to find out, what needs to be done.

There is a long-standing debate about the so-called black-white achievement gap. The claim is that black children perform considerably worse than white children of the same socio-economic class. This confounds those of us who assume that class is the main axis of educational inequality. If middle-class black children do worse than middle-class white children, the gap may not be addressed by simply redistributing wealth, or focusing resources on high-poverty schools.

Popular explanations fall into two broad categories. One side blames the blacks. They have, it is claimed, an anti-educational and oppositional culture, and the breakdown of the black family makes children uneducable.

Indeed, a cursory look at black popular musical culture suggests influences which are not entirely in synch with the aims of a decent education. And the proportion of black children not living with their natural fathers is double the proportion of white children. The other side blames the schools.

Schools are supposed to be imbued with white supremacist values compounded by racist teachers and school managers.

These two explanations of the gap suggest very different interventions. The “black culture” explanation blames the families and communities and calls for schools to separate children from them. A more progressive variant of it calls for eliminating poverty and discrimination in the labour market and criminal justice system. The “racist schools” explanation suggests the retraining of teachers and managers, and radical revision of the curriculum to better reflect black culture.

Most states have stayed neutral, but school districts with substantial numbers of black children have to take action. Many act on the “racist schools” explanation, re-educating teachers to be less racist.

The problem is that it is not clear there is a gap to worry about.

Certainly, black children perform less well than white children from families with similar incomes. But income is not the only measure of affluence.

Black families are likely to have considerably less wealth than white families with the same level of income, because the parents are more likely to have come from working-class or poor backgrounds. They are also more likely to be supporting less affluent extended families. When economists allow for family income and wealth, the achievement gap diminishes. When they allow for grandparents’ income and wealth (and thus the security of the families’ hold on middle-class status), the gap all but evaporates.

This undermines both explanations, because it undermines the phenomenon.

Some research suggests that low-income black children perform best with high-status white teachers and that black children are not more, but less, alienated from schools than their white counterparts. This dents the “racist schools” claim.

As better social science data and more sophisticated ways of analysing it become available, the gap seems less likely to exist. This is tremendously important.

First, if black children do just as well as their similarly situated white peers, that is a tremendous tribute to their communities and cultures, because no one disputes that there is still massive discrimination against blacks in labour and housing markets and the criminal justice system.

Second, schools trying to re-educate supposedly racist teachers may be doing a great deal of damage - not just in presuming that their employees are racist, but also in demoralising them, to the cost of the children in their classrooms.

Harry Brighouse is professor of philosophy and affiliate professor of education policy studies at Wisconsin university