Even as District public school eighth graders made a breakthrough last week by scoring above the national norm on a math test, their progress over the last two years was less than the national average.

This same group of students scored better on math when they took the test as sixth graders, and should now be further along in their development, according to a further examination of test results.

D.C. school officials, who last week focused attention on the eighth graders' achievement in surpassing the national norm in math -- a first for an eighth-grade class in the D.C. public school system -- now have begun to examine the inconsistent progress students have shown from year to year in secondary school classrooms.

"I'm very concerned," said James Guines, assistant superintendent of instruction.

"There's nothing wrong with the students. I need to look at the teaching and curriculum and also look at the test. It's not always true that the test does the same thing in grade eight as it does in six. The test is not perfect. We have to look at all of that."

Judging by national norms, the eighth graders should have improved their scores on the Comprehensive Tests of Basic Skills by at least 20 months beyond their scores as sixth graders, said Verne Dahl, spokesman for McGraw Hill Inc., which publishes the CTBS in Monterey, Calif.

Instead, their scores on the math test increased by only 16 months, according to an examination of test results.

Since the school year averages 10 months, students should make at least that much progress for each calendar year between tests, Dahl said.

By that standard, he said, the D.C. eighth graders actually lost some ground.

School officials now "need to analyze their test results and see which portion of the test students are not doing as well in and . . . determine what they need to do, if anything, in order to maintain adequate progress," he said.

The CTBS measures proficiency in reading, math, language, science, social studies, reference skills and science skills.

About 90 percent of the D.C. eighth graders who took this most recent test also took the CTBS test as sixth graders, D.C. school officials said.

Guines said that secondary school students should show impressive gains in coming years, as a specialized program to gauge and foster student progress, begun in the elementary schools in 1980, expands throughout the junior and senior high schools by September 1986.

The program, called the Student Progress Plan, gauges students' performance and requires them to reach basic minimum requirements before they are promoted from one semester to the next.

It has led D.C. elementary students to sustained achievement that surpasses national norms. Many elementary school students, in fact, are not only scoring above the norms but making year-to-year progress beyond the national average.

But the picture was somewhat different for this year's eighth graders.

In 1983, when they were in the sixth grade, they scored 6.9 in reading and 7.3 in math -- scores that exceeded the national norm of 6.8 for the first time, by one month and five months respectively.

This year, they scored 7.9 on the reading test, nine months below the norm; and 8.9 on the math test, one month above the norm. Thus the difference between the math and reading scores has increased. In 1983 their math score exceeded their reading by four months. This year, the math score was higher by 10 months.

Some groups of D.C. students have made steadier progress, even while not quite attaining the national norm.

This year's ninth graders, for example, scored one month below the norm in both math and reading. But three years ago, as sixth graders, these same students had scored two months below the norm in math and six months below the norm in reading.

Students who were in ninth grade in 1983 advanced their reading scores from 8.4 to 10.4 as they moved to the 11th grade this year -- proceeding at a normal pace.

They moved more slowly in math, however, advancing from 9.0 to 9.9 during that same period.

And in lower grades, there has been even better progress. Students who were in third grade in 1982 were at the national norm in reading and one month above the norm in math.

This year, as sixth graders, they surpassed the reading norm by one month and the math norm by three months, meaning they made greater progress than the national average.

Generally, progress is steadier in elementary schools because teachers follow the Student Progress Plan.

Also, many factors that tend to hinder performance on the secondary level do not exist in the elementary schools, officials said.

For example, the rate of absenteeism for pupils in grades one through six is very low, they said.

At the junior high school level, students begin enountering typical adolescent problems. Absenteeism begins to become a factor.

"Teen-agers think that they are grown and they don't like being told what to do," one teacher said.

Officials have been slow to implement the Student Progress Plan in the secondary grades because of the complexities involved in studying the curriculum, devising strategies and deadlines and retraining teachers to meet new standards, Guines said.

Meanwhile, school officials have introduced an Intensive Junior High School Instruction program in grades seven to nine. A spokeswoman described the program as a "philosophy" that touches all areas of instruction and extracurricular activities at the junior high schools.

As part of the program, which was implemented in 1980 and is credited for some improvement in test scores, "contracts" are sent to parents at the beginning of each school year that clearly state minimum requirements expected of each student and his family.

Under the agreement, students are to take notebooks home every day and their parents are to check to make sure they are doing their homework in a quiet place.

Also, students must have library cards.

Teachers are urged to assign homework four days a week and teach basic math, reading and writing skills in each classroom.