Southern Maryland's public school systems showed widespread improvement on standardized reading and math tests at four grade levels, according to scores released this week.

This is the second year that students in the third, fifth, eighth and 10th grades took the Maryland School Assessment tests, which are administered in the spring. The scores for 10th grade math were not available this week.

With a few exceptions, all four grade levels in Calvert, Charles and St. Mary's counties increased the percentage of students who passed the tests by scoring in the "advanced" or "proficient" categories.

The federal "No Child Left Behind" Act mandates that all students be proficient in reading and math by 2014. Schools must also break down student performance by race and income as well as enrollment in special education and ability to speak English. If one group fails to reach proficiency, a school may be forced to let students transfer to a different school, or, eventually, the nonperforming school could be taken over by the state. School systems will not know whether they have met the performance standards until mid-summer, officials said.

While all systems in Southern Maryland showed improvement, Calvert County had higher percentages of students passing the reading and math exams at all four grade levels, compared with St. Mary's and Charles counties.

"We've seen overall improvement in every single area," said Carol Reid, the assistant superintendent for instruction in Calvert County. "While we're elated at this point, it's guarded optimism until we see the disaggregated data."

In Calvert, about 85 percent of third-grade students passed the math test, the highest percentage in any category at any grade level in Southern Maryland. The lowest percentage of passing students in all three counties came at the eighth-grade level on the math exam. Of the three, St. Mary's scored the lowest, with 39.4 percent of eighth-grade students passing the math exam.

John H. Cox, assistant superintendent for instruction in Charles County, said students generally have more trouble with eighth-grade math because the material is more difficult.

"It's when you start solving for the unknowns that math takes a different turn," he said. "We need to get more students through the content sooner."

The biggest improvement in an individual category came in Charles County, where 14 percent more third-grade students passed the reading test. In St. Mary's, about 10 percent more fifth-grade students passed the math exam. And in Calvert, about 8 percent more eighth-grade students passed the math exam this year.

"Preliminarily, we did much better than last year," said Charles County Superintendent James E. Richmond. "The highlight is reading, which is one of the system's focuses . . . and specifically in the third-grade and 10th-grade levels."

Richmond said school officials in Charles are analyzing the results in each school and will develop an action plan for improving scores in certain areas.

"We aren't where we want to be, but we know where we want to go," he said. "We've got great staff and hard-working people."

In two categories, students' scores went down. In Calvert, a smaller percentage of 10th-grade students passed the reading test this year, dropping to 76.9 percent from 77.8 percent last year. In St. Mary's, eighth-grade students fared slightly worse on the math test, with 39.4 percent of students passing this year, compared with 40 percent last year. At some grade levels in all three counties, minority students' scores also decreased.

Reid said she was pleased to see the improvements in mathematics test scores because the Calvert system has put in place new programs to improve math education. At the middle school level, she said, students took assessment tests in the fall so teachers could establish how much they needed to improve before the standardized tests. Students also were assigned a special math problem of the week to help gauge progress. Calvert teachers also will take part in a summer school course to improve math instruction, she said.