Alexandria school officials said yesterday that the ethnic and economic diversity of the city's population is the main reason that Alexandria students have not fared as well in recent years on required basic skills tests as other students in Northern Virginia.

Test results released by Science Research Associates on Tuesday showed that while all elementary grades in the city exceeded the 50th percentile, the national average, for the first time in years, there was only slight improvement over last year's results.

"Our scores are always lower than Arlington and Fairfax," said James P. Akin, director of research, planning and evaluation for the city school system.

"Our average income level is lower and we have a much larger minority population in the public schools," he added.

Akin said that where ethnic and economic backgrounds of Alexandria students matched those of Fairfax and Arlington, Alexandria almost always fared at least as well as the other areas.

Virginia requires all fourth, eighth and 11th graders to take an ability test and skills test in reading, mathematics and English usage that have been developed by Science Research Associates.

Akin said he did not have this year's results broken down by school or ethnic group yet, but he said that in 1984, among white students in fourth grade, Alexandria registered reading scores in the 84th percentile, the same figure as that for Arlington whites and slightly higher than the results in Fairfax.

"If you look at it by segment of the population and by their economic background," Akin said, "we don't do any worse than anybody else."

Akin said that many of Alexandria's students come from foreign countries, and although they now speak English well, their scores are bound to be lower than those of students in a more homogeneous county, such as Fairfax.

Alexandria's public school enrollment is 47 percent white, 37 percent black and 16 percent other groups, according to school officials. By comparison, about 90 percent of Fairfax's public school enrollment is white.

Still, Alexandria officials are concerned that prospective students will be discouraged by the results.

"We have the exciting diversity of an inner city and some of the problems, too," said Lou Cook, Alexandria school board chairman. "We have to sit down and do a better job with the scores. But moving to Fairfax does not make you smarter." Alexandria School Officials Say Diversity Explains Slight Rise In Students' Scores City Pupils Still Lag Behind Other N. Virginia Areas By Michael Specter Washington Post Staff Writer

Alexandria school officials said yesterday that the ethnic and economic diversity of the city's population is the main reason that Alexandria students have not fared as well in recent years on required basic skills tests as other students in Northern Virginia.

Test results released by Science Research Associates on Tuesday showed that while all elementary grades in the city exceeded the 50th percentile, the national average, for the first time in years, there was only slight improvement over last year's results.

"Our scores are always lower than Arlington and Fairfax," said James P. Akin, director of research, planning and evaluation for the city school system.

"Our average income level is lower and we have a much larger minority population in the public schools," he added.

Akin said that where ethnic and economic backgrounds of Alexandria students matched those of Fairfax and Arlington, Alexandria almost always fared at least as well as the other areas.

Virginia requires all fourth, eighth and 11th graders to take an ability test and skills test in reading, mathematics and English usage that have been developed by Science Research Associates.

Akin said he did not have this year's results broken down by school or ethnic group yet, but he said that in 1984, among white students in fourth grade, Alexandria registered reading scores in the 84th percentile, the same figure as that for Arlington whites and slightly higher than the results in Fairfax.

"If you look at it by segment of the population and by their economic background," Akin said, "we don't do any worse than anybody else."

Akin said that many of Alexandria's students come from foreign countries, and although they now speak English well, their scores are bound to be lower than those of students in a more homogeneous county, such as Fairfax.

Alexandria's public school enrollment is 47 percent white, 37 percent black and 16 percent other groups, according to school officials. By comparison, about 90 percent of Fairfax's public school enrollment is white.

Still, Alexandria officials are concerned that prospective students will be discouraged by the results.

"We have the exciting diversity of an inner city and some of the problems, too," said Lou Cook, Alexandria school board chairman. "We have to sit down and do a better job with the scores. But moving to Fairfax does not make you smarter."