Christel House Academy South charter school, which was at the center of accusations former state Superintendent Tony Bennett changed Indiana’s A to F grading system to raise its grade, saw a strong rebound in its ISTEP scores in 2013-14.

After a long string of A’s, Christel House South fell to an F in 2012-13 after test scores made a dramatic drop and blamed problems with online testing as the reason. This year, it recovered nearly all of its lost ground by gaining 9 points to 71 percent passing. The school’s passing rate had been more than 70 percent the prior three years.

Deputy Mayor Jason Kloth said he was pleased to see the school return to the sort of passing rate that was routine in the past. Mayor Greg Ballard is the school’s sponsor, with responsibility for monitoring its performance and the power to decide if its charter is renewed to keep operating.

“We were impressed by Christel House’s acknowledgement of having some challenges last year and the corrections they made this year,” Kloth said. “We’re not surprised, under strong consistent leadership, to see their results improve.”

A scandal erupted in 2013 when emails shared with reporters by staff members working for Bennett’s successor, Glenda Ritz, showed Bennett and his lieutenants worried that Christel House might receive a C while they were at work on revising the state’s A to F school accountability system in 2012.

Bennett’s team made changes in the grading formula that resulted in the school maintaining its A for 2011-12. The school’s founder, philanthropist Christel DeHaan, had contributed to Bennett’s political campaign in the past.

A legislative investigation later deemed Bennett’s A to F changes “plausible” and the state’s ethics commission declined to bring charges against him based on the Christel House concerns. In July he paid a fine for a campaign law violation instead.

When Christel House was given an F for 2012-13 based on the test score drop some critics saw it is more evidence the school had received special treatment under Bennett. The school’s leaders, however, argued their scores were depressed by online testing glitches that interrupted ISTEP for thousands of students across the state and a large number at the school. The school appealed the F grade but was denied.

This year, their scores jumped back up.

“The fact that we had kids who couldn’t complete the test, it obviously had an impact,” said Carey Dahncke, the school’s former principal who is now CEO of a growing stable of Chirstel House charter schools. “We are disappointed that our appeal wasn’t granted. In our head, this makes it a little bit better.”

Kloth stopped short of agreeing with Dahncke that last year’s drop was entirely driven by the testing problems, saying there was never a definitive answer about what went wrong. The mayor’s staff expected a rebound either way.

“We look at school performance over the long term,” Kloth said. “They’ve gotten very good results consistently within (grades) K to 8. They have strong leadership and governance. We were confident the results they had were going to improve.”

Dahncke said the school made few major changes this year, as school leaders were confident they would be proven right that last year’s result was a glitch-driven aberration.

But one change the school did make was it administered ISTEP entirely on paper this year, taking a pass on the online option.

Christel House South’s focus now, Dahncke said, is on helping its students who still did not pass ISTEP to improve and putting the testing problems behind them.

“That’s water under the bridge,” he said. “You can’t go back an change it. Our supporters understood and continue to believe in the work we do. We think this verifies that.”