Fifty-five Prince George's County public schools failed to log high enough scores to meet performance requirements on state reading and math tests this year, officials announced Tuesday.

At the same time, 11 county schools that had not met state standards last year met them this year, which officials said signifies improvement at those schools. According to state guidelines, these schools have to post higher scores next year before the state considers them to no longer need corrective action. Yet, among Maryland counties in the Washington area, Prince George's had the most schools that failed to meet state requirements.

The results are from the Maryland School Assessment tests in reading and math taken this year by students in grades 3, 5 and 8. Reading results for 10th-graders were also released; 10th-grade math scores will be made public later this summer. Although students in grades 4, 6 and 7 also took the tests, their scores will not count toward school performance because this was the first year they took them.

The test scores are significant because the federal No Child Left Behind law mandates that all children be deemed "proficient" in reading and math by 2014. Schools that do not meet the standards will face sanctions and could be taken over by the state.

Schools are judged not just by how their students performed as a whole on standardized tests devised by each state, but by how those in specific subgroups fared. The subgroups include racial and ethnic minorities and students who speak limited English, live in poverty and are enrolled in special education programs.

If one of these subgroups fails, the entire school fails. Maryland is negotiating with the U.S. Department of Education to change the way that it calculates school performance.

Prince George's officials said the school system met benchmarks in 16 of the 18 categories, including the subgroups. That represents 89 percent of the areas that the school system was judged in, up from 56 percent of the categories that met benchmarks last year. Overall, the system failed to meet benchmarks in special education reading and math, areas that school systems throughout the state also struggled with.

Prince George's schools chief Andre J. Hornsby attributed that failure to the fact that the school system concentrates many of its special education students in particular schools, rather than allowing them to attend schools in their communities. Hornsby has pledged to end that practice.

"The way this county implemented special education programs, we tended to concentrate them in special locations, which is really not good," he said. "We should have them educated in their neighborhood schools. When you concentrate them in certain schools, it makes it an enormous challenge for those schools to overcome."

Hornsby, who became head of the school system in June 2003, said he also plans to focus on another subgroup -- those who speak little English. The county has seen a sharp increase in immigrants in the last 10 years.

"Going after those two groups alone is going to make all the difference in the world," Hornsby said.

Statewide, nearly 200 of Maryland's 1,430 public schools failed to meet targets in reading and math -- a substantial improvement from a year ago. State officials attributed that to a revamped statewide curriculum. But they also acknowledged that there were new, less stringent rules for assessing the subgroups.

Last month, the state released the actual scores from the tests, which showed that the percentage of students scoring proficient on both math and reading increased in Prince George's, even among subgroups. But in some cases, that was not enough to keep schools from being considered "in need of improvement" or close to it.

Schools that fail to meet benchmarks two consecutive years are labeled in need of improvement. At high-poverty schools that fall under that category, students will be allowed to transfer to better-scoring schools. A school that misses the target for three years in a row has to pay for low-income students to receive private tutoring. Schools that fail over several consecutive years could eventually face state takeover.

In Prince George's, 12 schools did not meet state benchmarks for the first time this year. They will not face any consequences from the state. For 35 schools, it was the second year of missing their target. Another eight schools that had already been identified by the state as in need of improvement did poorly again this year.

"We plan to continue to stay the course, to continue to focus on our school improvement plan," Hornsby said.

In his year as head of the 137,000-student school system, Hornsby has focused on improving reading instruction, provided additional training for teachers and removed unsuccessful principals. He also instructed teachers to test students more regularly so that they know what skills they have to concentrate on, rather than teaching students what they already know.

"We've got to get smarter about that," Hornsby said.