U.S. Education Secretary Margaret Spellings said her department plans to triple the number of disabled students that schools can partially exempt from annual tests required under the No Child Left Behind law.

Schools had been allowed to exclude about 10 percent of an estimated 6.5 million children with disabilities who qualify for special-education services, Education Department spokesman Chad Colby said. The new rule would excuse an additional 20 percent of students, or more than 1 million individuals, he said.

Those students with physical, cognitive or behavioral disabilities are given an alternative set of exams that are graded on a different scale, Colby said. Schools still must show annual progress with these students' results as they would with the regular tests, he said.

"At its heart, this policy is all about improving the way we educate and assess children with disabilities," Spellings said in a speech to policymakers and educators at Guilford Elementary School in Columbia, Md. "It's a smarter, more sophisticated way of serving their needs."

Spellings first proposed increasing the number of disabled students eligible for alternative assessments in April. She said yesterday that 31 states have signed up to implement the policy for this school year.

The new rule is still subject to a 75-day comment period before becoming final, the Education Department said.

The No Child Left Behind law requires nationwide testing to encourage school improvement. Schools that fail to make sufficient academic progress for two consecutive years must let students transfer to a different school in the district, then pay for tutoring in the third year.

Advocates for the disabled opposed the new regulation, saying it may increase schools' incentives to shortchange children with physical and academic problems.

"It doesn't take a brain surgeon to figure out that if you've got two kids in the room, and one's got to pass the test and one doesn't, where are you going to put your energies?" said Curtis Decker, executive director of the National Disability Rights Network in Washington.

The guidelines also fail to prevent states from maximizing the number of children eligible for reduced assessments, said Candace Cortiella, director of The Advocacy Institute, a nonprofit group in Marshall, Va., to help the disabled.

"This is definitely one of those times when, if you build it, they will come," Cortiella said.

Kansas, the only state so far that has conducted an assessment of students who should be eligible for alternative testing, found 20 percent of disabled students are qualified, Cortiella said.

The Education Department's research shows that across the U.S., 30 percent of disabled students should be eligible for the reduced testing standards, Colby said.