The S.C. Department of Education raised Battery Creek High School's report card rating after school leaders questioned the accuracy of the data initially used.
The school's 2010 rating moved to "average" from "below average," the Education Department announced Friday.
Battery Creek was one of eight schools across the state to receive a revised rating after data errors were found.
School report cards are required by the state Education Accountability Act of 1998 and use a mathematical formula to give schools one of five assessments -- excellent, good, average, below average or at-risk.
The report cards compile results of various state-mandated tests, as well as data on student-teacher ratios, attendance, per-pupil expenditures and average teacher salaries, among other data.
Battery Creek appealed its original rating, announced publicly in March, because it believed incomplete data had been used in the calculation.
It was able to document the identity of students with missing identification numbers that passed the state's high school exit exam. The exam pass rate is one factor in report card ratings.
Edmond Burnes, Battery Creek principal, said he is pleased the school was allowed to appeal. Burnes said he and the school's testing coordinator knew as soon as the rating was released something was wrong.
"We're pretty meticulous when we look at data," he said.
Beaufort County School District superintendent Valerie Truesdale said in a news release she is proud the appeal was addressed.
"One of the most important services from the state Department of Education is publishing accurate, timely data," she said. "We appreciate the state's correcting the data and the rating on Battery Creek High."
The Education Department says its website will be changed to reflect the new ratings and exit-exam pass rates.