Arlington elementary schools have for the first time reduced the overall gap in achievement test scores between white and minority students, giving a boost to school Superintendent Robert G. Smith's intensive effort to address the issue.

Newly released results of the Stanford 9 achievement tests show that the gap between non-Hispanic white students and Hispanic students in fourth and sixth grades shrank by two percentile ranks--the precise annual goal set by Smith and the Arlington County School Board in 1997. The gap between black and non-Hispanic white students was reduced even more--by six percentile ranks for fourth-graders and seven ranks for sixth-graders, as the scores of white and Asian students also rose.

In the fourth grade, non-Hispanic whites on average reached the 81st percentile, Asians the 76th percentile, Hispanics the 55th percentile and blacks the 49th percentile. Percentile scores show where students rank when compared with a sample of test takers representing the whole country, with the 99th percentile being the top and the first percentile the bottom.

For a test-taker to score at the 81st percentile, it means that 19 percent of the other test-takers did as well or better and 81 percent of other test-takers did worse.

Smith and the Arlington School Board were the only local school officials to call for an annual reduction of two percentiles in the achievement gap, although Fairfax County school officials set a target of reducing the gap between white and minority SAT scores by 10 percent.

Montgomery County Superintendent Jerry D. Weast has announced a plan for reducing the minority achievement gap while raising scores for all students, but he has set no numerical goals.

Arlington's chances for success looked shaky when last year's test results showed widening gaps in some grades. But Smith and the board persisted, joining a national network of districts that is pushing for more attention to minority students' needs.

Smith said yesterday that he was pleased not only with the scores but with the elementary schools' success in increasing achievement for all ethnic groups. "I think I have succeeded in focusing attention on what I want to happen," he said.

No other Washington area district has set such precise achievement goals for all grade levels, and few other superintendents nationally have taken the risk of pushing for targets that have been so difficult to achieve. The Minority Student Achievement Network, a national group of 14 school systems that Smith helped organize this year, is looking for ways to raise minority scores and is scheduled to hold its second annual conference in Arlington in late June.

Smith cautioned against reading too much into one year's test results. He said it will take time to determine which teaching methods are working best. But, he said, "I believe we are seeing these positive outcomes because of focused, high-quality instruction provided by teachers, focused leadership provided by principals, support for learning provided by parents and hard work by students."

Arlington, like many other school districts, has tried to raise achievement by urging more students to attend after-school and Saturday classes and summer school, as well as adding tutors and specialists in subjects such as reading. Most area districts have reported higher test scores in the past two years, although none have set annual targets as precise and broad as Arlington's.

Research shows that students from low-income families tend to have lower scores, and black and Hispanic children are more likely to come from low-income families than white children. Some research, however, indicates that middle-class minority students also score lower on average than their white counterparts, leading education groups to seek reasons for the discrepancy and ways to end it.

Arlington School Board member Mary H. Hynes said the county's effort grew from the realization that 60 percent of its students are from minority families, 40 percent are poor enough to qualify for federal lunch subsidies and many of them need more help. "There is nothing more pressing for our community, and we have to do it in the context of higher achievement for everyone," she said.

The Stanford 9 tests in English, math, science and social studies are given at the beginning of fourth, sixth and ninth grades in Virginia.