High-achieving children have made much smaller gains than low achievers under the No Child Left Behind Act and various states’ school-accountability laws, according to a report released today by the Thomas B. Fordham Institute, a nonprofit research organization.

Looking at student performance on the National Assessment of Educational Progress from 2000 to 2007, the report says that the scores of the bottom tenth of students rose substantially on the fourth-grade reading and mathematics tests and on the eighth grade math test. But, the researchers say, students in the top tenth “have made minimal gains.”

(Although the No Child Left Behind Act was not signed into law until January 2002, the researchers saw 2000 as an appropriate baseline because schools were already responding to the likely passage of the act as it was debated in Congress in 2001. The general trends that the report documents hold true in the period after the measure became law.)

Based on an analysis of student performance on the national assessment during the late 1990s, the report says that high-achieving students made bigger gains than low achievers in states without school-accountability systems, but smaller gains than low achievers in states with them.

The report includes the results of a survey of 900 public-school teachers, large majorities of whom described low-achieving students as a bigger priority for their schools and more likely to get their one-on-one attention than high achievers.

The reseachers found that those low-income black or Hispanic students who posted high scores on the eighth-grade math test were much more likely than low achievers with such backgrounds to have teachers who had at least five years of experience and had majored or minored in math. —Peter Schmidt