The Arlington School Board voted last night to give principals at its three popular alternative schools authority to consider race when selecting pupils to attend the schools.

After a month of debate, the board, on a 3-to-2 vote, said principals should "seek to achieve a diverse student body as well as consider the order of applications."

The policy did not set specific guidelines.

Until now, selection has been on a first-come, first-served basis. The board wanted to change the system in an effort to attract more minority pupils to two of the three schools, which have large white enrollments.

Some board members have said they believe the first-come, first-served system effectively discriminated against minority parents whose work schedules may not have allowed them to stand in the early morning or overnight waiting lines that have characterized the application process.

"We're all searching. We all hoped for some magical, perfect solution," said board member Gail H. Nuckols. "The best we can do is try something like this."

The policy change stops short of setting racial quotas, which the School Board's attorney advised against.

Instead, it relies on principals to make sure the racial makeup of a school reflects the county's racial mix. About 42 percent of Arlington's students are members of minority groups.

Board Chairwoman Dorothy H. Stambaugh, who has favored a lottery as a means of choosing pupils for the alternative schools, voted against the change, saying "the guidelines for principals are too vague." Board member Conchita Mitchell also voted against it.

Voting for the policy were Nuckols, Frank K. Wilson and Judy Connally.

The policy moves the application date to October of the year before a child would attend a school and directs school officials to actively recruit minority applicants.

"Word of mouth is the only thing that's going to sell this," said Mitchell.

H-B Woodlawn Secondary School, known for its open, independent atmosphere and consensus decision-making, has a 17.8 percent minority enrollment. Page Elementary School, which stresses a traditional, back-to-basics approach, is 10.1 percent minority.

Drew Model School, an experimental team-teaching elementary school in the predominantly black Nauck neighborhood, has a 40 percent minority enrollment.