The results of a series of nationally standardized and local tests given Arlington County pupils this year show their performance to be academically stable, say Arlington school officials who released the test results last week.

The academic performance report is the first in Arlington to include results of tests that were developed within the school system. Both standardized and local tests showed overall pupil performance to be stable over a three-year period.

There are specific areas that show great improvement and others that show need for improvement," said School Superintendent Larry Cuban. "But I am pleased with the overall student performance. It is well above national norms in most areas."

The local and standardized tests were administered to grades four, six, eight and eleven, totaling more than half of Arlington's school population of 19,100. Some tests were also given to second graders.

Cuban said elementary pupils tested showed improvement in reading and mathematics and high school pupils showed stable performance in these two areas.

"When we talk about stability in the school system we're talking about maintaining a level of education in the face of dramatic and frequent changes to Arlington schools," Cuban said. "Arlington schools have had to adjust to a steadily declining student enrollment combined with an increasing ethnic diversity.

Associate superintendent Harold Wilson said 32 per cent of Arlington pupils belong to minority groups representing 72 languages. Nearly all of these minority group children in the give grade levels where the tests were administered took the tests, Cuban added. Only a few students who cannot read or write English at all did not take them, he said.

Academic areas where the tests showed significant improvement in pupil performance included sixth and eigth grade mathematics. Although local tests showed third graders deficient in reading skills by Arlington schools standards, the scores of elementary pupils in reading were well above national norms on the standardized tests, Cuban said. Elementary pupils overall have shown steady improvement in reading during the past three years.

School officials said sixth grade test scores in mathematics "give cause for elation." The report says that the scores, 17 percentage points above national norms, are the highest sixth graders have achieved in five years and show significant improvement over last year.

Eigth grade math scores, 11 percentage points above national norms, also are higher than in previous years and show improvement in the last year.

Academic areas where the tests showed notable decline in student performance included fourth grade math, third grade reading and fourth grade reading. In the fourth grades, there was an increase in the number of pupils reading below grade level.

The standardized tests showed that Arlington fourth graders are 7 percentage points above the national norms in mathematics achievement, but that those scores are below their results in other academic areas tested.

In reading, third grade pupils who took reading tests developed by the Arlington school system did not reach what the school system determined to be "mastery levels" for reading.

Less than 80 per cent of third grade pupils mastered several reading skills covered by the local tests. The skills included determining a sequence of events in a story, drawing conclusions, finding main ideas, identifying details and making inferences.

In the fourth grade, the number of pupils reading two years below grade level has increased from five to seven since 1974. Cuban said reading specialists, after examining test results, are examining possible causes for the increase.

In lanaguage arts (grammar and spelling), eleventh graders fell 4 percentage points below the national norms on the standardized tests.

The report also showed that Arlington students taking the College Entrance Examinations scored well above the national average on both verbal and mathematic segments of the test and that their scores have remained relatively stable over five years.

The student performance report is available in public libraries, schools and the Arlington Education Center.