Improving high-poverty schools that have struggled for years is tough enough, but Atlanta has seen another factor making the task even more difficult: sexual misconduct among school leaders.

Three Atlanta school principals have resigned in the past three years after being accused of sexual relationships with teachers at their schools. All of the relationships took place at some of the state's lowest performing schools, schools that often churn through principals at a high rate — even without allegations of sexual misconduct.

High principal turnover has serious consequences for students.

Research shows it can take as long as five years to turn around a low-performing school. Having new faces in the principal's office each year can mean school improvement efforts must restart each time, making it harder to turn a school into a place where all students learn and feel safe. It can mean good teachers are less likely to stick around and lower performing teachers less likely to leave.

And sleeping with your staff is against Atlanta Public Schools policy.

It’s the kind of thing that should never happen, said Robert Robbins, Sr. who served as an Atlanta school administrator for 30 years before retiring.

“When you roll up on that campus, wherever it is, and you’re holding the title of principal or staff member, you have some awesome responsibilities,” he said. “It’s not you first. It’s the development of those children first.”

The latest case involves Boyd Elementary School, whose performance earned the school an "F" from the state five years in a row.

Boyd Principal Marcus Jackson was “a rooster, watching over a hen house,” the husband of a Boyd teacher wrote in a complaint The Atlanta Journal-Constitution obtained under state public records laws, claiming that Jackson made sexual advances to his wife.

At first Jackson and the teacher traded flirtatious text messages, but the exchanges and the relationship eventually turned explicit, with Jackson sending the teacher nude photos and repeatedly asking her to do the same, text messages reviewed by the AJC show.

Jackson resigned earlier this year soon after the husband complained. He had been at Boyd less than two years. By the start of this school year, Boyd will have had six principals in 10 years.

Reached by phone this week, Jackson declined to comment.

Atlanta Public Schools declined to make human resources and academic officials available to speak about principals leaving their posts after allegations of sexual misconduct and how turnover in the principal’s office affects students.

The district released a written statement: “Whenever Atlanta Public Schools has a principal vacancy during the school year, we have a process in place to identify experienced interim personnel to fill those positions to prevent minimal disruption to the learning environment.”

But at least one parent at a school whose principal left after alleged misconduct said the damage has been long-lasting.

In 2014, the principal of Young Middle School, Kelvin Griffin, resigned after district investigators found he had romantic relationships with both a teacher and a student's mother. Griffin denied having the relationships, but resigned because he felt the Atlanta school system wouldn't support him after its 10-month investigation, he said at the time.

Griffin’s departure threw a school striving to improve into chaos, said Dawn Brockington-Shaw, whose children attended Young.

Griffin’s recruiting trips to neighborhood elementary schools to persuade families to pick Young over a charter school stopped. Students angry over his sudden, unexplained departure started a letter-writing campaign to get their popular principal back.

In the following years, as Young cycled through four principals, much of the progress Griffin and community members had made toward improving Young was erased.

“All the work that we had tried to accomplish was ruined,” Brockington-Shaw said, though she is hopeful that Young’s current principal will pick up that school improvement work where Griffin left off.

Douglass High School principal Eldrick Horton resigned in 2014, shortly after a teacher told district officials he had retaliated against her when she did not respond to his texted sexual advances. Douglass High School, whose academic performance ranks among the bottom 5 percent of Georgia schools, has seen six principals in the past 10 years.

In a letter to the district’s superintendent, Horton admitted sending the texts, but called it a momentary lapse of judgment involving an old friend. He said he had not treated the teacher unfairly.

Atlanta school district spokesperson Kimberly Willis Green said she was not aware of any other cases of principals being accused of inappropriate relationships with staff.

Nationally, public school principals stay at their schools for a little over 4 years, on average. But at high-poverty, urban schools, principal turnover is even higher.

In Atlanta’s wealthiest public schools — North Atlanta and Grady high schools and the schools that feed into them — principals stay on the job about 7 years, on average, according to a 2014 district report. In the Douglass High School cluster where Boyd is located, where most students are from low-income families, the average principal tenure is less than 5 years.

Romantic relationships between supervisors, like principals, and staff could violate Georgia educator ethics rules, said Paul Shaw, head of the Georgia Professional Standards Commission ethics division, especially if the relationship took place at school or involved school computers or other school resources.

“We realize that they’re both adults and what they do on their own time is their own business. But when it affects the classroom or the school we may want to be involved a bit more,” he said.

He recommends that districts report them to the Professional Standards Commission, which oversees educator licenses. The commission could investigate and impose sanctions. None of the Atlanta cases were reported to the commission, Shaw said. At least two of the Atlanta principals — Horton and Griffin — were eventually hired by other schools in the metro area.