The Virginia Board of Education lowered the score needed to pass four Standards of Learning tests in social studies today, after more than a year of passionate complaints from schools across Virginia that say the tests are flawed.

The changes will mean the difference between passing and failing for thousands of students statewide, state officials said, which could also increase the number of schools that meet the accreditation requirements.

State officials disagree with the complaints, but the social studies tests -- more than any other SOL exams -- have frustrated and angered educators, who call them unfair and nearly impossible to master. Some officials have asked that the tests be eliminated until they are rewritten.

"I think the state Board of Education has done exactly the right thing," Loudoun Superintendent Edgar B. Hatrick III said. "The only unfortunate thing is that it wasn't done before now."

The move is the most high-profile change in a series of revisions to the controversial state testing program, which is now three years old. As recently as this summer, board President Kirk T. Schroder suggested adding an essay question to the exam, in hopes of making it a better assessment of student knowledge. But the idea was rejected by a board advisory committee. The standards themselves were rewritten last year to counter critics who said they were too broad and required too much memorization.

State officials have stood behind all the exams, including the social studies tests.

"The problem has not been the history test," said state School Board member Mark Christie. He and other board members said school districts have had difficulty incorporating the history and social studies standards into their lessons because of the volume of facts students are expected to learn.

"There's plenty of evidence to show that students in some districts are doing exceptionally well on that test," Schroder said. "Rather than point the finger, the board needs to act in a responsive way to make the necessary adjustments."

Many students across the state continue to perform poorly on the history and social studies tests even though they pass the other Standards of Learning exams. This year, only 47 percent of high school test-takers passed the U.S. history tests, up from 39 percent the year before. In comparison, 74 percent of students passed the Algebra I test.

In Fairfax, 19 out of 48 schools that didn't meet the state's benchmarks for accreditation would have done so if their students had scored higher on the history and social studies tests. Three of six Loudoun schools also failed to meet the state's benchmarks solely because of those tests.

Top school officials in those districts said they were glad the board lowered the passing scores, but are adamant that they have aligned their curriculum to the tested material in a comprehensive and timely way. The test is the problem, they said.

"We're teaching to the test here," said Fairfax Superintendent Daniel A. Domenech. "If the kids still aren't passing, the instrument itself has to be changed, not what they're being taught."

State school officials reviewed the passing scores of all 28 Standards of Learning tests, which are given annually to third-, fifth- and eighth-graders and high school students in core academic subjects. Beginning in 2004, high school students also must pass a battery of tests to graduate. In 2007, schools where fewer than 70 percent of students pass the SOL tests risk losing state accreditation and funding.

The board dropped the passing score from 26 to 25 on the 40-question, fifth-grade social studies test; from 33 to 28 out of 50 questions on the eighth-grade social studies test; from 36 to 32 out of 63 questions on the high school World History II test; and from 40 to 34 out of 61 questions on the high school U.S. history test.

The scores will be reviewed again in two years, said Shelley Loving-Ryder, the assistant superintendent for assessment and reporting. At that time, new standards for history and social studies, which the board adopted last year, take effect.

She said she expected thousands of students would pass as a result of the changes made today, but she could not estimate precisely how many more would have passed the tests this year if the amended scores had already been in place.

Passing scores for all 28 Standards of Learning tests were adopted by the board in 1998 based on recommendations from teacher committees. But in many cases, the board adopted a score at the high end of the range. In looking at the social studies exams, Loving-Ryder said she compared the current passing score with the median score of the recommended range.

She also looked at how students performed on the tests. In history and social science, the results are undeniable.

"Students are doing very well in math and English and not as well in history," Loving-Ryder said.

Several local educators who applauded the state's move said they didn't consider it a weakening of the testing program.

"I think if you look at the social studies and history scores," said Eric L. Stewart, the principal of Sully Elementary School in Loudoun, "it's clear things are out of mix. If this is the state's effort to balance it out, then it sounds like a good one."

Staff writer Rosalind S. Helderman contributed to this report.