The Columbus school district admits in a court filing that its employees made errors that could have resulted in bogus student-achievement gains on state report cards, and that they must stop.

Still, district lawyers have asked a judge to dismiss a lawsuit that says data-rigging disqualified students from academic help, saying the district is immune to liability under Ohio law.

Meanwhile, the plaintiffs — a father and his son, who attended a district middle school — amended their November lawsuit this week to ask a Franklin County Common Pleas judge to expand the list of defendants from Superintendent Gene Harris and the school board to the district’s data chief, one of his underlings and a group of principals.

“We contemplated naming all principals,” said John Sherrod, the attorney representing the plaintiffs. “But we decided to go with people where we believe there was direct evidence” that they altered student data.

Newly named as defendants are:

Steve Tankovich, the district’s now-reassigned data chief, who was responsible for collecting and reporting student data to the state.

Michael Taylor, who worked under Tankovich. District records show he altered tens of thousands of student records.

Michael Dodds, a former high-school principal whom Harris promoted to oversee a group of schools after he changed tens of thousands of records at Independence High. At his new position, he continued to change records at several schools, including some where he had no authority. He has been assigned to his home since July.

Amy Dennis, the former principal of Whetstone High, whom Harris promoted to be the district’s director of pupil personnel.

Pamela Diggs, the principal of Marion-Franklin High, and Cary Cordell, an assistant principal there.

District officials were still reviewing the new complaint and had no comment yesterday.

The lead plaintiff is Marvin Perkins, the father of a former Medina Middle School student. The suit alleges that the district deceived the public about school rankings, potentially causing students to be denied money for tutoring and other academic help. It seeks to be a class-action suit, and to recover money to pay for tutoring or other student needs caused by the district’s alleged data manipulation.

The district, in its response to the original complaint, said that it can’t be held liable for monetary damages because it is immune under Ohio law. The district maintains that only the Ohio Department of Education has authority to determine whether data has been improperly recorded, and only the department could recalculate to correct such errors.

The district has tightened its processes, restricting the number of employees who can alter data, creating a new “accountability committee” and buying a new student-information computer system, it argues in its brief.

Sherrod called those points “completely irrelevant.”

“It has nothing to do with what occurred from 2008 to the summer of 2012,” he said.

The complaint also asks for a protective order preventing the district from destroying documents. The district responded that the motion is baseless and should be denied.