At least 15 schools in Northern Virginia must give their students the option of transferring to other schools this year under the federal No Child Left Behind law, based on standardized test scores to be released today.

The schools, which receive federal funds because they have high proportions of low-income students, are subject to the sanction because they failed to make "adequate yearly progress" on state Standards of Learning exams for the second consecutive year.

Statewide, 28 percent of schools failed to make adequate progress in the academic year that ended in June -- an improvement over 42 percent the previous year. Ninety-one of the state's 1,805 schools will have to offer children the chance to transfer to a higher-performing school this year.

The federal law's goal is proficiency in math and reading for all students by 2014. Until then, the law requires schools to meet progressively higher targets in SOL test results as they aim at the goal. Meeting those targets is particularly difficult because some groups of students -- low-income students, certain racial groups, special-education children and those with limited English skills -- are tracked separately. If one group falls short, so does the entire school, even if the school's average scores surpass the targets.

Schools that fail to make enough progress for two straight years must create a plan for improvement, and those schools that receive federal funds tied to poverty rates -- called Title I funds -- also must allow students to transfer.

Virginia education officials expressed muted enthusiasm yesterday at the news that more schools had met the testing targets. Along with Virginia politicians, the education officials have been among the law's most vocal critics, charging that it muddies the state's efforts at test-based reform, which began in 1995. The state's Republican-led House of Delegates passed a resolution in January blasting the law, claiming that it will cost the state "literally millions of dollars that Virginia does not have."

In a statement, Gov. Mark R. Warner (D) pledged yesterday to continue to push for "common-sense revisions to the law." He also cited the latest results as evidence of the state's commitment to raising achievement.

"Even with the flaws . . . we had that many schools still meet those benchmarks," state Superintendent Jo Lynne DeMary said, adding that it means "they really are meeting the needs of their children."

Because there are scoring and participation requirements for two tests across as many as seven student groups, a school can have to meet as many as 29 targets. DeMary said 90 percent of Virginia schools either made adequate yearly progress or fell short in fewer than four targets -- many involving special-education students or those with limited English skills.

Arlington County School Superintendent Robert G. Smith said the law obscures the line between struggling schools that miss the mark in several categories and those that are doing well for the most part. He said schools that have improved significantly can be tagged with the same label as those that have changed little.

"We're characterizing schools and then putting them in this category as if they're schools you need to escape," he said, adding that the six Arlington schools that will allow students to transfer are quite similar to other county schools and that some are well-known for excellence. "It flies in the face of what parents know in many cases."

State officials, who emphasized that the results were preliminary, noted that more children passed the SOL tests in almost every group. Proponents of the law say it was crafted to bring about just that kind of progress, by forcing schools to report and be held accountable for groups that often have been ignored. But DeMary said Virginia already was headed there.

Last year, Maury Elementary School in Alexandria was the only local school required to allow the transfer option, and 14 percent of the student body exercised it, reducing the school's enrollment to 131. This year marks Maury's third on the list of schools that failed to make progress, meaning that its students must be offered tutoring at public expense.

Alexandria School Superintendent Rebecca L. Perry took aggressive action to improve Maury, including transferring an award-winning principal, Lucretia Jackson, to the school this year despite heated protests from parents at Jackson's former school.

"I do understand that Maury has many challenges," Jackson said yesterday in her office, where she was overseeing a summer program to prepare children for kindergarten. "But we have fantastic staff and parents here, and they are willing to accept the challenges." She said she already has set up a schedule for the after-school tutoring required by the law.

Margaret Ticer Janowsky, whose daughter is beginning first grade at Maury, said she and her husband decided not to transfer their child, as many Maury parents have done, "because we want to make this the best school for our neighborhood. . . . The teachers are fabulous and now we have this great principal who in just a month and a half has already done a lot for this school."

In Fairfax, the state's largest school district, two Title I schools -- Dogwood Elementary in Reston and McNair Elementary in Herndon -- must offer transfers. The status of six Title I schools remains unclear while officials recheck statistics.

Fairfax County's new superintendent, Jack D. Dale, said the district has made great strides, with 77 percent of its schools making adequate yearly progress compared with 45 percent last year. But he said the fact that a school's status often depends on the scores of only a handful of children highlights flaws in the law.

"The spirit of No Child Left Behind is very appropriate, but in all the details and regulations, it forces people to lose sight of that spirit," Dale said.

Fairfax educators have sent letters to parents at Dogwood and McNair and held meetings for them. They have set a Sept. 3 deadline for deciding whether to transfer children. Prince William County has set an Aug. 27 deadline.

Lynn Terhar, president of the Fairfax County Council of PTAs, said she has heard from parents who say they're feeling the pressure, and she encouraged schools to be as patient as possible as parents weigh their options.

"I think there's still a lot of confusion and misinformation out there. As is always the case, parents don't really focus on these things until it effects their child," Terhar said.

Staff writers Jay Mathews and Christina A. Samuels contributed to this report.

Arlington schools chief Robert Smith says the law obscures the line of school performance.To improve one school, Alexandria Superintendent Rebecca L. Perry moved a principal despite protests.