Average scores on Advanced Placement tests for Montgomery County high school students increased last year for the first time in the county's campaign to increase student participation in honors and college-level courses, according to a report released yesterday.

The school district reported that high schools last year continued to have great success in persuading more students to take honors, Advanced Placement and International Baccalaureate courses and the long and difficult AP and IB tests. Last May, Montgomery students took 13,689 AP tests, twice as many as four years ago.

Until last year, average test scores had declined as more students began taking the college-level tests, matching a national trend suggesting that the additional students were not quite as prepared for the challenge.

In 2002, however, the portion of Montgomery students scoring 3 or higher on the 5-point AP tests increased from 78 percent to 79 percent, and the average score inched up from 3.45 to 3.48. In 1998, 83 percent of AP tests in Montgomery were graded 3 or above, and the average score was 3.59.

A score of 3 will often qualify a student for college credit in one of the 35 subjects covered by AP tests. A federal study has shown that students who take honors, AP or IB courses in high school, even if their grades are mediocre, are much more likely to graduate from college than those who get good grades in easier courses.

Montgomery School Superintendent Jerry D. Weast said he believes the increased average scores were the result of efforts by teachers and principals to raise the level of instruction in all grades so that more students would be ready for AP and IB classes in high school, as well as better prepared for college or the workplace.

"We are catching up in the level of preparation, as well as the rigor of teaching, up and down the line," Weast said.

Montgomery has gone to unusual lengths to gather data on how different groups are performing in AP classes and on the tests. It is one of the few districts where principals receive annual reports on how many of their minority students, as well as low-income students and speakers of limited English, are taking the demanding courses and exams.

Although minority students are taking more honors and AP classes and tests, yesterday's report showed that their participation rates still lag behind those of white and Asian American students. The portion of African American students taking at least one AP test increased from 7 percent to 15 percent in four years, and the portion of Hispanic students rose from 10 percent to 18 percent. The percentage of non-Hispanic whites taking at least one AP test jumped from 28 percent to 47 percent, and the portion of Asian American students rose from 34 percent to 54 percent.

Beyond the tests, even more students are enrolled in honors or AP courses, said schools spokesman Brian Porter. He said the portion of African American students enrolled in at least one honors or AP course increased from 32 percent in 1999 to 44 percent last year. On that same scale, participation for Hispanics rose from 32 percent to 39 percent; Asian Americans, from 70 to 78; and non-Hispanic whites, from 66 to 75.

Honors courses are generally designed by local schools and teachers, while AP and IB courses offer centralized curriculums to prepare students for AP or IB tests, which are written and graded by outside experts. AP tests are three hours long, and IB tests can be as long as five hours.

Yesterday's report did not provide figures for IB courses and tests, which are offered at Richard Montgomery, Bethesda-Chevy Chase and Springbrook high schools.

The report showed that of 6,785 students taking AP tests last May, only 1 percent were in limited-English programs, only 1.8 percent had disabilities qualifying them for special education, and only 3.9 percent were poor enough to qualify for federal lunch subsidies.

Superintendent Jerry D. Weast attributed the improved test scores to more rigorous classroom instruction in all grades.