Acting Schools Chancellor Kaya Henderson asked the D.C. inspector general Tuesday to investigate reports that sharp gains in some standardized test scores may have been the result of cheating.

She made the request after a USA Today investigation found unusually high rates of erasures in which students apparently corrected their answer sheets for standardized tests between 2008 and 2010.

More than 100 D.C. public schools had the unusual rates of erasures, in which wrong answers were replaced by correct ones. One seventh grade classroom, at Noyes Education Campus in Northeast Washington, averaged 12.7 wrong-to-right erasures per student on the 2009 DC CAS reading test. The citywide average that year was less than one per test.

Henderson also released a series of reports from a test security firm the District hired to investigate elevated erasure rates at eight schools, including Noyes, in 2009. The firm, Caveon Test Security, said it found no evidence that staff tampered with answer sheets.

While Henderson said she had complete confidence in Caveon, she said she referred the matter to Inspector General Charles J. Willoughby to eliminate doubts about test security and affirm the integrity of the teachers involved.

“These poor teachers are now tainted,” Henderson said. “They were cleared by an investigation. I feel like I owe it to them to remove the taint.”

But District testing procedures may face added scrutiny. D.C. Council Chairman Kwame R. Brown (D) said Tuesday evening that he might hold hearings on the erasures. Such an inquiry could feature subpoenas for school officials who declined to speak to USA Today, including Wayne Ryan, former principal at Noyes. Ryan has since been promoted to an instructional superintendent.

“We are seriously considering looking deeper into this matter,” Brown said, “maybe subpoenaing people to come testify about who told who to do what.”

Ripples from the erasure disclosures also have reached former chancellor Michelle A. Rhee, whose high national profile as an education reformer was based in part on test score growth during her three-plus years overseeing the D.C. school system.

In an interview with PBS’s Tavis Smiley that was broadcast Tuesday evening, Rhee pushed back at those questioning the validity of District test scores, suggesting that critics doubt the ability of D.C. schoolchildren to excel academically.

“Often times when the academic achievement rates of a district like D.C. go up, people assume that it can’t be because the kids are actually attaining higher gains in student achievement but that it’s because it’s something like cheating, which in this case was absolutely not the case,” Rhee said.

In addition to Noyes, the schools Caveon investigated for their 2009 erasures rates were Birney, Burrville, Stanton and Tyler elementaries, Shaed and Walker Jones education campuses and Sousa Middle School.

Versions of the Caveon reports made public Tuesday evening are heavily redacted, concealing even the names of the school principals. They consist of brief narrative descriptions of interviews with teachers whose classrooms were “flagged” for high erasure rates. In some instances, teachers who Caveon officials sought to interview were not available. All interviewees denied any improprieties and said all security procedures were followed.

In summaries of their findings for each school, investigators attributed high erasures to factors such as improved test preparation that called for students to look over the answers carefully before finishing. Caveon officials also repeated positive comments they received about improved academic culture at the schools under scrutiny.

“We were told that there has been a culture change at Tyler and the school is now much more orderly and discipline has improved,” investigators John Olson and Dave Couchman reported.