The news came as a blow to Marumsco Hills Elementary School last week, just days before the start of school.

Under federal law, the 500-student school in Woodbridge will be required to offer its students transfers to other schools, based on poor results on one part of the Virginia Standards of Learning tests. It is the only school in Prince William County that will have to offer transfers.

The transfer policy is mandated by the No Child Left Behind Act, which ushered in a new way of judging school performance.

Schools are now evaluated by their math and English test results in several subgroups -- white, black, Hispanic, poor, students with disabilities and students with limited English skills -- in addition to the student body as a whole.

In Virginia, each subgroup must have at least 50 students to be counted, and Marumsco Hills, with a large population of poor and Spanish-speaking children, has students who fall into one or more subgroups. Other schools might do worse on the tests, but if they don't have enough students to fill a subgroup, that subgroup does not count toward meeting "adequate yearly progress."

The rationale behind No Child Left Behind is that schools will no longer be able to disguise poor performance among some groups of students through averaging. If any one subgroup performs poorly, the whole school, as well the district, fails to make adequate yearly progress. Schools such as Marumsco Hills, which receive federal funds because they have high proportions of low-income students, are the only ones subject to the "school choice" sanction.

Marumsco Hills did not meet the required pass rate in the English reading and writing test taken by students with limited English skills. About 52 percent of the students passed, instead of the 61 percent required. Parents now have the option of letting their children staying where they are or transferring them to Swans Creek Elementary or the new Williams Elementary.

"I'm absolutely miserable," Marumsco Hills Principal Mary Joanne Alvey said, speaking from her home as she pored over test results. The school is fully accredited by state standards, which are different from the federal rules.

Alvey said she is confident she can raise test scores to passing levels in the upcoming school year. To be the only county school facing the sanction was tough, she said.

"The staff is so good. We have some top-notch teachers. I don't want them to think they aren't. . . . It's very sad," she said.

Although the test scores had consequences for Marumsco Hills, the county did well overall. Prince William has 18 schools that get money from the federal government through Title I, because they have high numbers of poor students. Fourteen of those faced the possibility of transfers this year because they did not make adequate yearly progress the previous year.

Eleven cleared the hurdle. Two other Title I schools, Dale City and River Oaks elementary schools, are checking their test scores with the state; their status is not yet determined.

Fourteen other schools did not make adequate yearly progress, but because they don't receive federal Title I money, they face no potential transfers. But they must develop improvement plans if they fail to meet the standard two years in a row.

"We were pleased with the improvement," said schools Superintendent Edward L. Kelly.

Talking about Marumsco Hills, Kelly said, "This doesn't mean that it's a bad school at all. There's a lot of different ways of measure the achievement of a school."

In Manassas, Jennie Dean and Baldwin elementary schools faced the possibility of instituting transfers but were able to improve their performance and meet the federal standard. The status of three other schools is yet to be determined.

"I'm not surprised," Baldwin Principal Jeff Abt said, adding that the community and teachers came together this year to work with students, particularly those with limited English skills. "But it's not over. We're getting ready to do it all over again."

In Manassas Park, three elementary schools met the federal standard, and one school's status is yet to be determined.

At Marumsco Hills, Alvey wasn't sure what the outcome of the school choice rule will be. Letters have been sent home to parents explaining the procedure. She said the school has many programs that cater to its students, including English as a Second Language teachers at every grade level and small classes.

"One of the best places in the whole school division for a [limited English-proficient] student in the school division is our school," Alvey said.

Deborah Chambers, parent of a fourth-grader at Marumsco Hills, said the No Child Left Behind rules create a distorted picture of schools.

"If you just look at [adequate yearly progress], you're missing part of the picture," said Chambers, who also has an older child who went through five years at the school.

She is not considering transferring her child.

"Absolutely not," she said. "And it bothers me, the effect [the results] will have on the teachers. We have the smaller classrooms, and we have the dedicated teachers."