Principal Selena Dukes Walton testified Monday that she remains "very qualified" to oversee her elementary school because she had been unaware of the massive cheating by teachers on a test to determine how well they were educating students.

Walton agreed students were harmed by the cheating but told the Atlanta Public Schools tribunal she was blameless for the malfeasance at Slater Elementary School in 2009.

"I am not responsible for something I did not know about," she said. "I'm not responsible for the teacher."

Walton is the first principal to face an APS tribunal after a state investigation uncovered evidence that about 180 educators in the school system -- including 38 principals -- were involved in test cheating. As the school system's top authority at Slater in 2009, she is accused of failing to investigate reports of cheating, failing to oversee testing to prevent widespread cheating that occurred that year at the schooland creating an environment that pressured teachers to cheat.

APS principals were under a tremendous amount of pressure to meet testing goals, according to state investigators. Under the system Beverly Hall set up when she was superintendent, principals who did not meet academic targets within three years would be replaced. Hall replaced 90 percent of principals during her tenure, according to the investigation.

This pressure was one of the primary reasons cheating in Atlanta was so widespread, according to investigators. Principals placed the same stress on teachers, humiliating them or threatening to fire them for low test scores.

Among the accusations Walton faced Monday was an assertion by a school system lawyer that the principal had publicly derided teachers whose students had scored low on the Criterion-Referenced Competency Tests.

An expert from Georgia State University testified Walton should have known cheating was the only plausible explanation for the number of wrong-to-right corrections in at least 30 of her classrooms during testing to measure academic progress.

Mary Beth Walker, dean of the Andrew Young School of Public Policy at Georgia State, said the number of wrong-to-right erasures on the CRCT was so great that the odds the changes were legitimate corrections ranged from one-in-1,000 to more than one-in-200,000.

“There is no credible explanation that has been offered except that cheating occurred," she said.

Walton's attorney, Borquaye Thomas, said cheating didn't necessarily implicate the principal.

The Governor's Office of Student Achievement compiled a report on the erasures for the spring 2009 CRCT and then investigated schools where a high number of corrections improved test scores. The investigation found that some teachers corrected answers on the test, gave the correct answers to students or allowed students to correct them the next day.

A tribunal of three retired educators is hearing evidence to determine whether to uphold APS Superintendent Errol Davis' recommendation to terminate Walton's employment contract.

Two other tribunals were  scheduled for Tuesday but have been canceled. Lera Middlebrooks, a proctor at Perkerson Elementary School, was accused of cheating by a teacher there. Middlebrooks resigned, school district spokesman Keith Bromery said. Angela Gardner, a teacher at Bethune Elementary School who admitted cheating, retired, Bromery said.

The state investigation concluded that APS staffers, for perhaps as long as a decade, worked in secret to transform testing failures into successes by changing wrong test answers into correct ones. Some administrators either covered up the behavior or ignored it, the investigation said.

Fewer than 90 educators implicated in the investigation are still employed by the district on paid leave.

Schajuan Jones, who taught at Slater in 2009, testified that she witnessed another teacher brazenly correcting test answers and reported it to the testing coordinator, who did not address the issue immediately.

“She continued to erase whole sections of the test," Jones said of the teacher. “I asked what she was doing and asked her to stop, and she pretty much ignored me.”

Walton had also told teachers shortly before the test specifically how many students could fail in their classes, Jones said.

Sharon Reeves, one of the lawyers representing the school district, called attention to the timing of Walton's warning on the pass-fail ratio, suggesting it was designed to pressure teachers to cheat if necessary.

But Jones said she had never felt any pressure to cheat. Reeves asked whether Walton warned her not to cheat, a question Walton's lawyer suggested missed the mark for a professional educator.

“Does a principal have to tell you not to cheat on the CRCT?”Thomas asked Jones.

“No sir,” Jones said.

Reeves said upcoming witnesses in the hearing, which is expected to reconvene later this month, would make it clear Walton was responsible for fraudulent testing that allowed students to progress in grades despite being unprepared academically.

Walton created a culture that pressured teachers to cheat -- publicly ridiculing teachers whose students did poorly on the test -- and refused to provide monitors during the testing to ensure students and teachers didn't cheat, Reeves said.

“What we have here today," Reeves said, "is a very sad story of a principal who abysmally failed in her duties by pressuring her teachers to change their test scores and turning a blind eye.”

Staff writer Ty Tagami contributed to this article.

WHERE THEY STAND NOW

Fewer than 90 educators suspected of cheating remain on the Atlanta Public Schools payroll, including teachers and administrators. They can make their case to keep their jobs before an APS tribunal. Once the hearings are held and terminations recommended, the matter goes to the school board for approval. Once approved by the board, the employees are terminated immediately. This happens regardless of their intent to appeal, APS spokesman Keith Bromery said. Where the cases stand:

33

Number of final resignations/retirements that have been received since late February

7

Number of hearings in progress or postponed at employee’s request

4

Number of educators terminated after a tribunal hearing

50

Number of letters sent to educators outlining charges and the school district's intent to terminate

32

Number of educators notified their contracts will not be renewed. Some will have the option of a hearing.