WASHINGTON — An elementary school principal’s claim that she saw teachers erasing answers on students’ test sheets had reached District of Columbia Schools Chancellor Kaya Henderson’s desk within 24 hours of the alleged incident in late 2010, according to emails obtained by The Associated Press through a public records request.

Henderson was notified about the alleged cheating by two officials with the Washington Teachers’ Union, the emails show. However, school system officials did little to investigate the specific claims and never interviewed the principal about them, largely because possible cheating at the school was already under investigation, school officials said.

The former principal, Adell Cothorne, said the emails show the school system essentially ignored her allegations.

Cothorne alleged in a federal whistleblower lawsuit last year that she saw a guidance counselor, an administrator and a teacher erasing students’ answer sheets on the day students took a city-issued standardized test at Noyes Education Campus. Noyes had been touted as a success story under Henderson’s predecessor, Michelle Rhee. The U.S. Department of Education named it a National Blue Ribbon School in 2009 after students’ proficiency in reading and math improved by more than 50 percentage points over three years.

The scores at Noyes have dropped precipitously since then. In 2009, 84 percent of Noyes students were proficient or better in reading, and 63 percent were proficient in math. In 2013, 30 percent were proficient in both subjects.

In 2011, a USA Today investigation found questionable wrong-to-right erasures at more than 100 schools in the district. Investigations by the city and the Department of Education found isolated cheating — including at Noyes, where some employees were fired — but not the widespread cheating suggested by the USA Today report.

The alleged cheating occurred during a high-pressure environment in which teachers and principals can be rewarded financially for improving test scores and fired if the scores drop. Several cities have weathered cheating scandals in the dozen years since the No Child Left Behind law made high-stakes testing a federal priority, including Atlanta, where 35 educators were indicted, and Philadelphia, where three principals were fired last week for their roles in an erasure scheme.

Wayne Ryan, the Noyes principal who preceded Cothorne and oversaw the huge gains, was promoted in 2010 to a central office position supervising numerous principals, including Cothorne. According to Cothorne’s lawsuit, Ryan and his staff were rewarded with a dinner at Ruth’s Chris Steak House after he won a bet with Rhee about raising test scores. Ryan no longer works for the school system, and officials would not discuss the reasons for his departure.

When Cothorne went public with the cheating allegations, Henderson said there was no record of Cothorne having reported what she claims to have seen. The AP requested emails referencing Cothorne and Noyes, and the school system responded in December, nearly 11 months after the request was filed.

The emails don’t show that Cothorne directly informed her superiors. But they show that union official Herb Thomas alerted Henderson to “an allegation involving the Noyes EC principal observing teachers changing students test scores.” Thomas sent that email on the afternoon of Nov. 4, 2010. Cothorne has alleged that she saw the teachers erasing answer sheets the previous evening.

The chancellor, then serving in an interim capacity following Rhee’s departure, replied to Thomas and copied in three other people, including Erin McGoldrick, then the school system’s accountability chief, and asked her to be in touch with the union’s chief of staff.

McGoldrick responded, “Absolutely. We were informed of this allegation. … We are finalizing the investigation of the allegation.” She later wrote to Henderson that she would update her in their next face-to-face meeting.

McGoldrick, who no longer works for the school system, declined to comment to AP. But according to school system spokeswoman Melissa Salmanowitz, McGoldrick’s statement about finalizing the investigation referred to the ongoing probe of cheating at Noyes and not the new alleged incident.

Henderson and other top school system officials made no attempt to contact Cothorne to clarify what the emails were referring to, and Salmanowitz said there are no records indicating that the school system began a new investigation into improprieties on the November 2010 test. The test was a low-stakes exam, essentially a practice run for the tests later in the school year that measured student proficiency.

“Noyes is perhaps the most investigated school in D.C. Public Schools,” said Pete Weber, who now oversees testing integrity for the school system. “I think it’s very clear that there just aren’t unturned stones at Noyes Elementary School.”

Salmanowitz, who did not make Henderson available for comment, said in a statement that the emails don’t reveal anything new about the school system’s response to Cothorne’s allegations. She said the school system takes all cheating allegations seriously.

But Cothorne said the response — or the lack thereof — is telling. If there was any ambiguity about whether the emails referenced a new incident of cheating, Cothorne said she would have been happy to clarify.

“They didn’t take it seriously at all, clearly,” Cothorne said. “They pay attention to what they want to pay attention to. Those things that show the plight of D.C. public schools, they try to sweep it under the rug or excuse it away. How does anybody not address that kind of situation of a testing impropriety, especially when the school has a history of it? You’re not addressing it because you want it to go away.”

Clay White, who was chief of staff to then-union president George Parker, said in an email to Henderson that the union had sent two field representatives to investigate but was unable to substantiate the allegation. He stressed the urgency of the situation in his email, which was sent at 2 a.m. on Nov. 5, 2010.

“I wanted you to know the allegations and for us to continue to demonstrate our real collaboration spirit … to inform you of this matter immediately,” White wrote.

The U.S. Department of Education could not substantiate Cothorne’s allegations, and she voluntarily dismissed her lawsuit in July. She said she didn’t have the money to pursue it further. She now works as an education consultant.

Cothorne said she regrets that there is no paper trail of her having reported the incident. She claims that she reported it by phone that evening to two school system officials, both of whom denied to AP that such conversations took place.

“I reported it to who I thought I needed to report it to. They assured me that it would be handled. I trusted that it would be handled,” she said.

Last month, Washington was hailed for its gains in reading and math on the federally administered tests known as the Nation’s Report Card. However, the district still has the largest achievement gap between black and white students of any city tested, and there remains a chasm between the city’s best schools and its worst on its own assessments.

The student body at Noyes is 94 percent black and 5 percent Hispanic, and 99 percent of its students are eligible for free and reduced-price meals, an indicator of poverty.

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