FOR 15 years, since the passage of George W. Bush’s No Child Left Behind act, education reformers have promoted standardized testing, school choice, competition and accountability (meaning punishment of teachers and schools) as the primary means of improving education. For many years, I agreed with them. I was an assistant secretary of education in George H. W. Bush’s administration and a member of three conservative think tanks.

But as I watched the harmful effects of No Child Left Behind, I began to have doubts. The law required that all schools reach 100 percent proficiency as measured by state tests or face harsh punishments. This was an impossible goal. Standardized tests became the be-all and end-all of education, and states spent billions on them. Social scientists have long known that the best predictor of test scores is family income. Yet policy makers encouraged the firing of thousands of teachers and the closing of thousands of low-scoring public schools, mostly in poor black and Hispanic neighborhoods.

As the damage escalated, I renounced my support for high-stakes testing and charter schools. Nonetheless, I clung to the hope that we might agree on national standards and a national curriculum. Surely, I thought, they would promote equity since all children would study the same things and take the same tests. But now I realize that I was wrong about that, too.

Six years after the release of our first national standards, the Common Core, and the new federal tests that accompanied them, it seems clear that the pursuit of a national curriculum is yet another excuse to avoid making serious efforts to reduce the main causes of low student achievement: poverty and racial segregation.