The Bush administration continues to tweak its landmark education legislation, announcing on Monday that the testing requirements will be eased by reducing the number of students a school may test without running afoul of the law.

This measure is the fourth move in as many months to ease the law's restrictions. It is expected to cap a flurry of responses to concerns from states and schools.

The new policy, which will apply to the current school year, allows schools leeway to bypass current No Child Left Behind Act (search) rules that require schools to give math and reading tests to at least 95 percent of students, including 95 percent of all subgroups of students, for instance minority or disabled youths.

The plan had been to make sure that schools don't leave out lower-performing students on test days in order to make themselves look like they are performing better than they are.

But under the new plan, the average proportion of students tested over two or three years only need be 95 percent, so schools could test 93 percent of students in one year and 97 percent in another. The new rule also will apply to subgroups of students.

Students who are enrolled but out of classes because of medical emergency will also be exempted from the number used to calculate the percent of students.

Many schools had complained that under the previous rule they may be unable to get federal funds due to them just because a few students had failed to take the test. The concerns have not been measured to see if this had been a significant problem, but anecdotal stories suggested some real hesitation.

Schools that get federal poverty aid but don't make progress goals at least two years straight face mounting sanctions, from having to offer transfers to risking state takeover.

"We are listening to parents and educators and making adjustments," Education Secretary Rod Paige (search) said in announcing the new policy Monday to the National School Boards Association conference in Orlando. "But we are not willing to sidestep or ignore the heart of No Child Left Behind — making sure that all children count."

Paige has agreed to ease other rules since December, including rules on disabled children, limited-English-speaking students and teacher qualifications.

State officials say that the administration has been taking steps to ease the tight rules, but the rules are still very strict.

"It's the first time we've had any recognition of the issues we've raised over the last two years, in terms of their willingness to address them," said Michael Bird, federal affairs counsel for the National Conference of State Legislatures (search). "In that regard, they're to be commended for listening, although we still have some root problems with the law."

Among them, Bird said, is a view among states that the federal government hasn't provided enough money to pay for its requirements, from data collection to teacher training.

The Bush administration says that's not true.

No Child Left Behind, the most sweeping federal education law in a generation, is the centerpiece of Bush's education agenda. Aimed at improving minority achievement, it won strong bipartisan support but has since faced opposition over key provisions and funding.

First Lady Laura Bush, also speaking in Orlando, urged school board members to support the law. She said it is based on the premise that "all children must have access to high-quality schools regardless of their skin color, their disability or their ZIP code."

The Associated Press contributed to this report.