The number of South Carolina students who passed the state's high school exit exam on their first attempt in 2009 declined from last year's high of 80.8 percent, the State Education Department reported Tuesday.
The dip, to 76.1 percent on the High School Assessment Program, comes after three consecutive years of improvement and confounded education leaders, who had hoped the state was on an upward trajectory.
A total of 51,437 students took the English portion; 51,368 took the mathematics test.
"We have racked our brains on why we didn't continue on this upward trend," State Superintendent Jim Rex said Tuesday.
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Rex said he is worried that the economic downturn is playing a factor in the decline but is reluctant to draw conclusions on the basis of the results of one year.
Districts statewide have lost about $600 million in general and Education Improvement Act funding during the past two years, and while administrators have tried to make districts leaner without affecting classrooms, that has not always been possible.
"We estimate we have about 1,000 fewer teachers than we had last year," Rex said. "We have seen after-school and summer programs cut, so there is maybe an apprehension at some point that we are going to see some effects."
Students take the HSAP exam, which includes separate tests on English Language Arts and mathematics, in the spring of their 10th grade year.
If they fail one or both sections, they retake the failed section of the exam until they pass.
The tests are scored on a scale of 1 to 4. South Carolina requires a score of 2 to pass.
HSAP scores also factor into high school Adequate Yearly Progress ratings under the federal No Child Left Behind law, which requires that all students score at a level of "Proficient" or higher by 2014.
Rex expects the federal law to be modified so states like South Carolina, which have installed higher benchmarks, won't be judged so harshly under the federal guidelines.
"States like ours that have pretty rigorous expectations started looking pretty bad earlier (under No Child Left Behind), but now it is catching up to all of them," Rex said.
He expects the current administration to adopt a growth model that would measure real progress rather than requiring states to meet arbitrary goals.
Tuesday's results were quickly highlighted by critics of public education.
The president of a group that advocates legislation to help parents send their children to private schools said parents should be worried.
"Each and every child in South Carolina deserves access to great classrooms, tailored instruction and a meaningful diploma," said Randy Page. "No one's child should be a 'random blip.'"
Before 2004, South Carolina high school students had to pass the Basic Skills Assessment Program to graduate - a pass-or-fail test developed in the 1980s. The High School Assessment Program is based on the state's more rigorous academic standards crafted under a 1998 state law.
Rex, who has announced as a Democratic contender for governor in 2010, has touted innovations in South Carolina's education system, including implementation of more choices for parents. Those include public charter schools, magnet programs, single-gender programs and the "virtual school" program.
He said lawmakers, too, need to step up to the plate.
"I always say it is great to have high expectations of students, teachers and administrators," Rex said. "But we also have to have high expectations of our policy makers."