Southern Maryland's high school class of 2005 generally scored higher than the 2004 class on the SAT, according to results released Tuesday by the College Board, the test's publisher.

St. Mary's County students achieved their highest scores ever. Graduating seniors at all five Charles County high schools recorded improved results. In Calvert County, the overall score declined slightly as the percentage of students taking the test increased.

The average combined verbal and math scores were 1086 points in Charles, 1059 in St. Mary's and 1050 in Calvert. The statewide average was 1026.

SAT scores are often viewed as a good indicator of a high school's academic caliber. But testing experts warn against using SAT scores alone as the measure of a school system because such factors as parental income and participation rates influence results.

The 2005 SAT marks the end of the familiar two-part test, on which the maximum possible score was 1600. Starting next year, SAT results will be reported on a third test, on writing, and 800 points will be added.

Over the past five years, the average combined score in Charles has increased by 55 points -- a trend the school system attributes to a long list of SAT preparation courses offered during the school day, after school and throughout the summer.

John H. Cox, assistant superintendent for instruction, said the personalized program helps students "understand the test, know how to pace themselves and focus on what they really have to know. That's moved us to another level."

La Plata High posted the highest score among Charles schools, jumping 30 points to 1138. The county's lowest-scoring school, Lackey High, posted the largest gain over last year's results, rising from 987 points to 1036.

The gap between black and white students persisted, though it narrowed somewhat. The average score for black students in Charles increased from 932 to 981, compared with an increase from 1110 to 1133 among white students.

Although the county's average scores increased, the percentage of students taking the test dropped from 36.9 percent to 32.5 percent. Statewide, the participation rate increased from 68 percent to 71 percent.

The relatively low rate of students taking the test in Charles reflects the school system's philosophy about which students should take the test.

Charles administrators believe that students should be well prepared to take the exam if it is required as part of their post-graduation plans. For instance, about 600 seniors, or 37 percent of last year's graduating class, said they planned to attend the College of Southern Maryland. The community college does not require the SAT, so high school counselors did not advise those students to take the test.

Superintendent James E. Richmond explained that approach. "My goal has been to reach every student that needs to take it to be successful, and I've been assured by our principals that we are," he said.

"We've never denied, nor would we discourage, anyone from taking it, but what we're trying to do is to give them the proper counseling," he said.

Richmond said the participation rate is "right on target" with the percentage of students who attend a four-year college. In 2004, 37 percent of the graduating class enrolled in a four-year college. That year, 36.9 percent of students took the SAT.

Charles Board of Education Chair Margaret Young disagrees with the system's approach and wants it to encourage more students to take the exam. She said students will have more options after graduation if they participate.

"Students need to keep their opportunities open. To do that, you take the SAT. You don't skip it," she said. "I am very disappointed that our rate does not mirror the state's."

In Calvert County, which prides itself on having one of the region's top school systems, SAT scores dropped by three points to 1050. The average scores on the math and verbal portions were 525.

Cathy Page, coordinator of system performance for Calvert's schools, attributed the drop to the county's efforts to get all students -- not just the most academically inclined -- to take the SAT. The percentage of graduating seniors taking the test increased last year by more than two points to 56.6 percent.

"We are reaching students who are not necessarily our very top students," Page said. "We are opening opportunities for them."

The highest-scoring school in the county was Northern High, where the average combined score jumped 17 points to 1068, and the percentage of tested seniors increased by 9 points to 65 percent. Northern teachers and staff members said they push all students to sit for the exam.

"We have special-ed students we encourage to take the SAT," said Principal George A. Miller.

Miller said he is not concerned that encouraging low-scoring students to take the test will drag down the school's overall results.

"I don't worry a whole lot if scores go up or go down," he said. "I would much rather see kids exploring their potential rather than me playing a numbers game."

Calvert officials also noted with pride that the achievement gap between white and black students narrowed. The average SAT score was 1071 for whites and 894 for blacks -- a difference of 177 points. Last year the gap was 183 points.

"We have been engaged in school-wide initiatives to support our African American students," Page said.

The number of blacks taking the test also increased, though the 35 percent of black students who sat for the exam still represented a lower percentage than that of whites taking it.

At Huntingtown High, which opened last fall as the county's fourth high school, scores were among the lowest in Southern Maryland. The school was the only one in the county whose combined average score, 998, did not exceed 1000.

Page said the scores were low because seniors who should have gone to Huntingtown last year had the option of staying in their old high schools. She said Huntingtown's graduating class of 185 students last year was unusually small.

"I think that many students who were highly involved in their home schools chose to stay there," she said. "Many of them were our high-performing students."

In St. Mary's County, the class of 2005 recorded a 33 point jump in the combined average score, pushing it to 1059. Superintendent Michael J. Martirano said that was the county's best performance ever.

St. Mary's students averaged a score of 534 on the math test and 525 on the verbal, above the state averages of 515 and 511, respectively.

"It's just good news all across the board," Martirano said. "We're really proud."

Leonardtown High School had the highest score, at 1078, followed by Great Mills High School, at 1053, and Chopticon High School, at 1035. The largest increase came at Great Mills, where the total score went up 43 points over the previous year's results.

"It's incredible," Martirano said. "Their highest ever." Leonardtown High School students increased their SAT scores by 41 points, and Chopticon's scores went up by 10 points.

Between 2001 and 2003, St. Mary's County SAT scores increased from 999 to 1042; they dipped to 1026 in 2004 and increased to 1059 this year. Martirano attributed the rise, at least in part, to a program that pays for all students in the 10th and 11th grades to take the pre-SAT test. The school system also uses software that allows students to take practice tests.

"Then just the continued focus on the rigorous curriculum," Martirano said.

Staff writer Joshua Partlow contributed to this report.