Anne Arundel high schools slipped in performance on two of three annual Maryland High School Assessments this year, with roughly two-thirds of students passing exams that all graduating seniors will be expected to pass by 2009.

Meanwhile, three of 12 Anne Arundel high schools failed to meet adequate yearly progress requirements in the federal No Child Left Behind law, according to a separate set of data also released Tuesday by the state.

High School Assessments, given to students as they complete benchmark courses in algebra, government and biology, have been overshadowed by the more comprehensive Maryland School Assessments, but they will gain currency when this year's freshmen become seniors. The class of 2009 will have to pass the High School Assessments to earn a standard Maryland diploma.

Anne Arundel's worst drop-off was in biology: The pass rate fell to 66 percent this year from 75 percent last year. The pass rate declined from 73 percent to 69 percent in algebra and rose from 65 percent to 67 percent in government.

The declining scores are atypical for the Anne Arundel system, which has become accustomed to steadily rising performance data in three years under Superintendent Eric J. Smith. School officials scheduled a press briefing for Tuesday to discuss the new scores, then abruptly canceled it.

Smith and other officials said the scores give a somewhat deceptive impression of how well students are actually doing in those courses. Smith has made it a priority to teach challenging courses to younger students; last year, for example, 2,300 students took the Algebra I course in middle school. As a result, many of the county's top students aren't taking High School Assessments and aren't counted toward the overall pass rate.

"A lot of our kids take algebra and geometry in grade eight, and that's a goal in itself," said Adam Milam, coordinator of research for Anne Arundel schools. "These are generally some of our highest-achieving kids."

Milam said students are apt to take the assessments more seriously in their senior year, when the tests become key to earning a diploma.

Overall, Maryland's public high school students fared worse on the assessments: Pass rates dipped in algebra and biology and rose in government, mirroring the results in Anne Arundel. Results of a fourth exam, in English, will be released later this year.

Severna Park High School posted the highest overall pass rates among Anne Arundel schools in algebra (77 percent) and biology (85 percent), while Arundel High attained an 80 percent pass rate in government.

The Maryland education department also released the remaining scores of the Maryland School Assessments yesterday: geometry scores for 10th-grade students and the so-called adequate yearly progress reports for every high school, based on the math scores and on graduation rates.

Three Anne Arundel schools -- Arundel, Glen Burnie and North County high schools -- failed to make adequate progress, a measure set under the No Child Left Behind law and designed to chart the progress of students across racial and socioeconomic lines.

All three schools fell short in a single area: mathematics performance among special-education students, one of eight statistical subgroups examined under the federal mandate.

Milam said the school system was preparing to appeal the findings. Past appeals based on special-education test scores have often prevailed because of changes to the federal law that allow school systems to exclude some special-needs students from the statewide tests taken by most students.

"We're talking about anywhere between two and 10 students" at each school, Milam said "If they'd made it, we would have made AYP."