Here are the mobility percentage rates of some metro Atlanta school districts:

Clayton County 31.0

Atlanta Public Schools 29.8

DeKalb County 27.9

Marietta 26.2

Rockdale County 22.0

Henry County 20.6

Douglas County 20.3

Fulton County 18.7

Gwinnett County 17.0

Cobb County 15.9

Cherokee County 12.4

Fayette County 10.4

Forsyth County 8.5

City of Decatur 5.5

Source: Governor’s Office of Student Achievement.

On a recent Friday morning, Dunleith Elementary School teacher Charmaine Joseph welcomed a new student to her kindergarten class.

The boy picked up an iPad and, without asking his teacher, stood with a group of his new classmates.

“Honey, you just got here,” the teacher said. “How do you know where you are supposed to be?”

The boy was the fourth new student enrolled that week at the Marietta school, principal Nikea Hurt said.

On one day in November, seven new students arrived at Dunleith, which has about 900 students. A week or so before that, three more children became Dunleith students.

What’s taking place at Dunleith is not unique.

An average of one in six Georgia students transfer from one school to another during the school year, according to a recent study by the Governor's Office of Student Achievement, the first time the state has conducted such research. Educators call it the student mobility or churn rate, and it makes teaching tougher.

Each year, hundreds of thousands of Georgia students switch schools, many due to family financial challenges. Among them, the highest percentage move to other districts.

In most cases, the new school — and teacher — is held accountable for how the student performs on state proficiency exams. Not fair, some teachers say.

An Atlanta Journal-Constitution review shows schools with high mobility rates are poor performers academically. The 25 metro Atlanta schools with the highest student mobility rates were an average of 20 points behind other schools on the state's College and Career-Ready Performance Index. (The AJC did not include alternative schools or schools for special education students.) The index formula includes student performance on end-of-course and standardized tests, improvement on those exams and the school's success in closing the achievement gap among low-income and minority students.

Several studies show a similar trend in other states.

“The more children moved, the lower the standardized test scores,” said West Chester University associate professor Donna Sanderson, who did her dissertation on student mobility among fifth-graders in the Philadelphia suburbs.

Sanderson also noted some other students in classes with high mobility can also fall behind, as teachers work harder to help the new pupils catch up.

Sanderson and other researchers have recommended ways to improve student performance in schools with high mobility rates. Some ideas, such as immediately assessing new students’ academic ability, are being carried out in metro Atlanta. Other suggestions, like providing transportation for students to stay at their school rather than attend a new one, are rarely followed.

Some state officials caution against concluding there is a cause-and-effect relationship between high mobility and student achievement, saying lower test scores could be attributed to many factors. The state report does not examine whether there is a correlation, but recommends additional research.

Student mobility is not an issue some educators discuss, or want to talk about publicly. Some teachers did not respond to the AJC’s request to talk about how newer students’ test scores affected the teachers’ evaluations. Clayton County school administrators declined the AJC’s requests for comment and to visit a school with a high mobility rate.

Clayton had the highest average student mobility rates in metro Atlanta, 31 percent, according to the report. That means 31 percent of Clayton students started the school year at one school but did not finish it in that same school. Atlanta Public Schools, DeKalb County, Marietta and Rockdale County rounded out the top five.

Educators in high-mobility districts attribute the frequent movement among some students largely to economics. Parents or guardians lose their job and many suddenly move. Many of these communities have large numbers of apartment complexes offering “first month free” rent specials that entice some low-income parents seeking to save a few bucks. The five local districts with the highest mobility rates also have the highest student poverty rates.

Marietta Superintendent Emily Lembeck said in an interview that the district’s high mobility rate has hurt test scores and graduation rates. Marietta, which has a large number of apartment complexes, has been looking for ways to improve academic performance among those students for a decade. Each school year, Lembeck makes a visit to the apartment complexes along Franklin Road — where one in seven Marietta students live — to talk to parents about how they can help their children. The district has created a program where parents help other parents with newly-enrolled students acclimate the children to Marietta schools.

At Dunleith, new students are immediately tested to determine their math and reading skills. Students who are behind are put in computer labs where they get extra academic help. New students are paired up with a classmate who becomes their assigned “buddy.”

“At this age, they want to help,” Joseph said of the veteran students. “They want to be buddies.”

The Atlanta and DeKalb school districts both conduct a similar assessment of a new student’s math and reading skills. In both districts, teachers and administrators share and review information about the student to determine how much help he or she needs. Atlanta has a team of student support team coordinators that works with school leadership to help the new students.

Some Georgia principals and administrators say it’s often difficult to educate students who transfer in from other states because it frequently takes a long time to get their academic records, if they get them at all. The state report found that students arriving from another state or country account for 17 percent of student mobility. Officials in DeKalb and Marietta said they’d like to see the state pursue ways to get those records much faster from other states.

Many teachers also complain that their evaluations are too tied to the academic performance of students that they don't have for large chunks of the school year. Georgia students who are enrolled for at least 65 percent of the school year are included in a teacher's effectiveness score.

Some administrators, like Morcease Beasley, DeKalb County’s executive director for curriculum, instruction and professional learning, sympathize with teachers. He meets monthly with a group of about 150 teachers to discuss teacher evaluation issues. Beasley said he would support additional research into whether the 65 percent rule is fair to teachers. He also believes state lawmakers need to study the reasons for student mobility.

“It’s tied to the economic viability of our state,” Beasley said. “Everyone has a role to play to see that improve.”

State Sen. Lindsey Tippins, a Cobb County Republican who chairs the Education and Youth committee, said schools need more human resource help when a new student arrives to lessen some of the administrative work done by teachers. Tippins, a former Cobb school board member, suggested some schools could set aside more money for such purposes when the state revises its Quality Basic Education funding formula. Tippins also agreed states need to share student records more quickly.

“I think it’s something we need to pursue, but it’s not going to be a quick fix,” he said.

Education scholars like Sanderson suggested it will be a challenge for years to come because we are a more mobile society.

“We move a lot more now at this time in history than we used to,” she said.