The retention rate for new teachers in Hawaii’s public schools improved this year, but the staffing shortage remains severe, with more than 1,000 of 13,000 positions filled by teachers who aren’t fully qualified.

The retention rate measures how many teachers remain on the job five years after joining the Department of Education. That figure rose to 54 percent in this school year, up from 52 percent last year, and a step toward the state’s 2020 goal of 60 percent. Out of 985 new teachers hired in the 2012-13 school year, 533 are still teaching.

Hawaii has long struggled to hold onto its teachers, with the high cost of living and the state’s isolation contributing to the problem. Nearly a quarter of all teachers exiting Hawaii’s public schools say the reason for their departure is that they are moving elsewhere.

“Any time that we can hold on to our teachers is a good thing,” said Corey Rosenlee, president of the Hawaii State Teachers Association. “The ultimate goal is we want a highly qualified teacher in every classroom.”

Statewide, there are 12,309 teachers on the job this year who have completed state-approved teacher education programs, out of a total of 13,320 positions, according to data released this week. That figure, 92 percent, represents a slip from 93 percent last year.

The rate is worse among special-education teachers. Statewide, 86 percent of special-education teachers now on the job had completed state-approved education programs, the same as last year.

David Miyashiro, executive director of the nonprofit Hawaii KidsCAN, said it may be time to consider a substantial pay differential for special-education teachers, recognizing the challenges they face and how much time they put in after school on individual education plans.

“The work that goes into teaching special education, you don’t even see the extra hours that go into it,” he said. “Our current system treats teachers as ‘one size fits all.’”

Rosenlee said the union has proposed additional pay or time off for special-education teachers or a cap on the number of students they must handle, but the suggestions have been rejected in negotiations with the state.

“We don’t have enough people who are willing to be special-education teachers because they are not willing to take on the load, and because of the load, that causes them to leave, so it’s just that cycle,” he said.

The number of teachers overall who are choosing to leave their jobs, through resignation or retirement, has climbed in recent years. Altogether, 1,075 teachers opted out in the 2016 school year, up from 934 five years earlier, according to the Department of Education’s 2016 annual employment report. Data for 2017 are not available yet.

Teachers cited “retirement” and “relocation” as the top reasons for leaving Hawaii’s public schools, each accounting for 24 percent of total voluntary teacher separations in the 2016 school year, the report showed. Nineteen percent said they left for other “employment opportunities.”

Another 16 percent cited “personal reasons,” followed by 6 percent blaming “workplace environment issues” and 4 percent opting to continue their education. The rest did not specify a reason.

The number of teachers trained locally can’t keep up with demand, and turnover is high among people recruited from the mainland. The issue is a national one as well, with fewer people overall choosing teaching as a career.

The Department of Education and the University of Hawaii have been collaborating on efforts to build up the cadre of teachers in the islands.

A “Grow Our Own” initiative is allowing substitute teachers, educational aides and emergency hires who already have bachelor’s degrees to earn full teaching credentials at no cost while keeping their jobs. In exchange for stipends that cover the cost of tuition, candidates agree to teach for at least three years in local public schools.

A UH campaign, “Be a hero. Be a teacher,” is also working to improve the image of teaching and encourage more students, working professionals and retirees to consider teaching as a career.