Public school systems in Calvert and St. Mary's counties this week reported lower scores on the state skills assessment tests taken last spring, while Charles County had a slight increase in its scores.

St. Mary's composite score dropped one point to 47.8 percent, while Calvert's score dropped 1.3 percentage points to 52.5 percent. Charles County posted a composite score of 43.6 percent, up 1.7 percentage points from the previous year.

The scores, released yesterday, are for the Maryland School Performance Assessment Program (MSPAP), a battery of tests given each spring to third-, fifth- and eighth-graders in public schools throughout the state. The tests, administered last spring, measure student performance in reading, writing, language usage, math, science and social studies. Scores reflect the percentage of students performing satisfactorily.

Statewide, 43.8 percent of students earned a satisfactory score on the most recent tests, 0.3 of a percentage point below the previous year. The slight drop comes after years of steady improvement. The overall score means most Maryland students remain far short of the state's goal of 70 percent reaching satisfactory scores by 2000.

The MSPAP exams are the state's main tool for determining whether schools are preparing children properly. Unlike the typical standardized test, MSPAP does not ask multiple-choice questions, instead prompting students to write short essays, draw maps and perform science experiments.

With its higher score, Charles County improved its ranking among the state's 24 public school systems from 19th last year to 17th this year. St. Mary's slipped in the rankings from 10th to 13th this year. Calvert, meanwhile, remained at the No. 6 spot.

Kent County, a small rural community on the Eastern Shore, surged to the top of the pack, leaving last year's top-ranked Howard County in second.

Charles County Superintendent of Schools James E. Richmond attributed the gain, which for the second year in a row has boosted the county's state ranking, to a reading improvement program implemented in 1997. Each elementary and middle school in Charles now has a reading resource teacher, and at-risk and high-achieving readers participate in reading programs each summer.

Despite the gain, Richmond said he was hoping for higher scores. "I'm delighted we're on the way up again, but I was hoping it would be more. . . . More importantly, I believe we are on the right track but we need to do a lot more."

Some Charles schools made big jumps in their scores: Malcolm Elementary's composite score rose from 48.9 percent last year to 61.2 percent this year, much closer to the state's 70 percent satisfactory standard. Others dropped significantly: Mount Hope-Nanjemoy Elementary's score fell from 37.8 percent to 22.2 percent.

In St. Mary's County, Superintendent Patricia M. Richardson said school officials could not explain the drop in scores until they analyze the data school by school, adding that the drop was "of great concern to us."

One school's decline in scores drew particular attention. Town Creek Elementary School in Lexington Park, which last year received much praise for exceeding the state's 70 percent satisfactory standard with a score of 75.5 percent, slipped to 64.9 percent this year.

"We caution people not to make a major change with just one year of data," Richardson said. "They really need to focus on the trend. When you test different students with different instruments, there is going to be room to go up or down."

Calvert County Superintendent of Schools James R. Hook said he was concerned that his school district's scores have not made any significant improvements in recent years, but pointed out that many of the school systems in the top half of the state rankings have had similar plateaus and dips.

"It's much harder to make gains when you're at the top," he said.

Hook said he has many initiatives in place--such as an intensive reading program, a class-size reduction plan and a new extended-day kindergarten program--that eventually should result in higher scores. But he said that he expects some community members will begin to lose faith in the exams if school districts do not improve their overall performance.

"I think you'll have some people try to question the validity of the test," he said. "When you have whole school systems that have sort of plateaued . . . and are working as hard as we are and not getting where they need to be, someone needs to look at why."

CAPTION: MSPAP Results in Southern Maryland (This graphic was not available)