All states that meet federal criteria will now be allowed to take part in the U.S. Department of Education's 2-year-old experiment with "growth models," which let states measure individual students' achievement gains as a way of ensuring accountability under the No Child Left Behind Act. After originally capping participation at 10…

In the debate over the future of the No Child Left Behind Act, policymakers, educators, and researchers seem to agree on one thing: The federal law's accountability system should be rewritten so it rewards or sanctions schools on the basis of students' academic growth. The U.S. Department of Education recently reaffirmed the Bush administration's…