Maryland's public high school students largely fared worse this year on a battery of standardized tests that will be required for graduation in 2009, the first statewide slip in scores since the tests were introduced three years ago.

State education officials released the results yesterday for three of the four required tests -- algebra, biology and government. Results of the English exam, which was revised this year, will not be available until late fall, state officials said.

The percentage of students passing the government exam improved slightly, inching up a half-percentage point to 66.4 percent. But that small gain was outweighed by larger drops in algebra and biology, as well as poor showings in all three subjects by black and Hispanic students.

Gary L. Heath, an assistant state superintendent who oversees accountability and assessment, said school systems are exploring the best ways to structure and present test curricula. But state officials attributed the lower scores mainly to students dismissing the importance of the exams.

"I'm not panicked at this point," State School Superintendent Nancy S. Grasmick said. "I don't think we're going to see any significant improvement until we're talking about this class that's entering ninth grade, because the students don't believe it really counts."

State officials pointed to gains on the state test in geometry as an example. Scores in 20 of Maryland's 24 school systems improved on that exam, which is a key factor in rating individual schools' performance, Heath said.

But it will be the algebra test -- not geometry -- that students must pass to get their diploma. This year, about 54 percent of students passed it, a 5-percentage-point drop from last year. Results for black students also dropped by more than 5 percentage points, with 30 percent passing the test. The pass rate for Hispanic students fell nearly 8 percentage points, to 42 percent.

About 58 percent of all students passed the biology exam, down 3 percentage points. Results for black students fell by nearly 5 points, to 34 percent.

Overall, female students outperformed male students.

Local school systems mirrored the statewide results, with some small gains coupled with larger declines.

Montgomery County recorded a slight uptick in the percentage of Hispanic students passing the government test, from 58.9 percent to 59.5 percent. But scores dropped, sometimes by several percentage points, among all other minority groups in all three subjects.

In Prince George's County, scores on the three exams dipped across the board, putting the county second to last of the 24 school systems. Just one high school, Eleanor Roosevelt, did better on the algebra test than the state average. At Potomac, Fairmont Heights and Forestville high schools, the passing rate on the algebra test was 10 percent or less.

"The challenge is clear," said Leroy Tompkins, chief accountability officer for the Prince George's system. "We've got a lot of work to do. We've been trying to create a sense of urgency among the high schools."

Pass rates fell in Anne Arundel and Howard counties on two of the three tests. Scores rose in Anne Arundel by 2.5 percentage points in government, to about 67 percent. Howard had an increase of 0.3 percentage points in algebra.

Officials in Calvert County were ecstatic over a 25-point jump in the percentage of students passing the government exam, bringing the total to 82 percent, the highest in the state. But the results were more sobering in algebra and biology, where scores fell after two years of gains. A third of students failed the algebra assessment.

In Charles County, the percentage of high school students who passed the tests dropped by about 5 points or more in all three subjects, causing concern among school officials who had hailed the past two years of solid increases.

"It doesn't make it okay, but it tells us that this is not simply a Charles County drop, that it's a statewide issue," said John H. Cox, assistant superintendent for instruction. "I don't think our teachers taught any less effectively. I don't think our kids were any less prepared."

The High School Assessments will become mandatory for graduation in 2009. By then, half the states will have implemented such high-stakes exit exams, affecting more than 70 percent of high school students, according to the Center for Education Policy, an independent nonprofit advocacy group.

This year's freshmen will be the first students affected by the policy. Students will take the tests at the end of their courses in those subjects and will have several chances to retake the exams if they fail, state officials said. Many incoming freshmen took the algebra exam in seventh or eighth grade.

A case study of an undisclosed Maryland school system released this summer by the Center for Education Policy showed that few students understand the purpose of the High School Assessments or how and when they will be required for graduation.

Still, the study found that the tests have begun reshaping classrooms. Schools have shifted their best staff members to teach test subjects, and class exams are often modeled after the state tests. Teachers spent more time reviewing curricula on exams and test-taking skills, which helped focus instruction but also left little time for more creative lessons, the report found.

But the biggest unknowns remain how students will react to the exams once they are fully implemented and whether the tests will mean the difference between a diploma and a dropout.

"It's a little hard to draw a lot of conclusions," said Terry Alban, director of assessment for Howard County schools. "With high school kids, motivation is a big deal."

Staff writers Ann E. Marimow, Nick Anderson, Joshua Partlow, Amit R. Paley, Fredrick Kunkle, Daniel de Vise and Lori Aratani contributed to this report.

Test results for all school systems and individual schools can be viewed at www.mdreportcard.org.