JACKSON, Miss. (AP) — The Mississippi Department of Education announced Wednesday that it has invalidated some students’ results on state-mandated tests after an investigation found irregularities with how testing was conducted at 12 schools in five districts.

The department said results on most of the 934 tests were invalidated because of an extremely high level of similar responses and instances of answers being changed from wrong to right.

Problems were found at seven schools in Jackson; two schools in Hollandale; and one school each in Canton, Greenville and Wilkinson County.

“We recognize and appreciate that the vast majority of schools properly administer state assessments,” Ray Morgigno, interim state superintendent of education, said in a news release. “However, interference in state testing corrupts the integrity of the assessments and deprives students and families of receiving a true and accurate measure of student learning and achievement.”

The invalidated tests make up less than two-tenths of 1% of the 578,515 tests administered in the spring, the department said.

The department notified superintendents in the five districts about testing irregularities on Aug. 15 and gave them 15 working days to conduct an investigation.

District leaders in Canton and Jackson found that 57 educators, administrators and staff violated test security rules. The districts took disciplinary action against the employees and reported them to the state Department of Education Office of Educator Misconduct.

School employees who violate test security rules face further disciplinary action that may include suspension or revocation of their teaching licenses, and possible criminal charges.

The Greenville, Hollandale and Wilkinson County districts did not identify school employees who violated test security rules. But the Department of Education said it is conducting test security and educator misconduct investigations in each of these districts.

Mississippi requires students to pass a state-mandated reading test before moving from third grade to fourth. Schools that promoted from the third grade with invalidated English Language Arts scores will be required to provide those students with additional support to ensure the children are reading proficiently.

Students with invalidated high school test results are required to retake the exams this school year because the assessments are required for graduation.

The portion of tests invalidated in each grade and subject range from 8% to 94% of tests taken in each subject at each school, the department said. Schools with invalidated scores in 10% or more of their state assessments will not receive a letter grade for the 2022-2023 school year and will have their accreditation status downgraded or withdrawn.