New London - The city's school district hired 40 new teachers, or nearly 15 percent of its staff, for the school year that began Monday, and officials are trying to find out why so so many teachers left.

"We're not sure yet,'' Superintendent Nicholas A. Fischer said Tuesday. "We're gathering data and analyzing exit interviews."

The district, which has about 270 teachers, has about a 10 percent turnover rate annually, Fischer said.

By Aug. 15, 28 new staff were hired for positions from kindergarten to 12th grade. But the week before school started, another dozen teachers put in their notices.

When school started Monday, there were still five vacancies, Fischer said, so substitutes from Kelly Services were assigned to classrooms without teachers. The substitutes will remain until permanent teachers are in place, he said.

Margaret Curtin, chairwoman of the Board of Education, said she awaits a report from the superintendent on exit interviews to explain the high turnover. But she speculated Tuesday that teachers could be leaving for higher-paying positions.

"I know Groton, East Lyme and Norwich pay more than we do,'' she said.

Uncertainty in the district, which is under the leadership of state-appointed Special Master Steven Adamowski, may also have a bearing on the high turnover rate, she said.

"I wouldn't like to work in a system where we don't know what's going to happen,'' she said.

Rick Baez, president of the New London Education Association, said the number of teachers who have left the system is "alarming" and "the number is growing." Each year, more and more experienced teachers are leaving, he said. He, too, is looking forward to a report from the administration on the exit interviews.

"I think 40 is a huge number," said Baez, a fifth-grade teacher. "You can't sustain an education system without having people who have experience in teaching."

Among the reasons teachers are departing, he said, is low pay and low morale. Teachers have had little to no pay increases during the past four years, he said. Those who started in the district four years ago started at $42,500 and are still making about the same, he said. Teachers with comparable experience in surrounding communities are earning more, he said.

According to the teacher contract database at ConnCAN, a website of 170 teacher contracts in the state, in 2012, a first-year teacher with a bachelor's degree earned $42,598 in New London. In East Lyme it was $40,722; Groton, $44,971; and Norwich, $45,178. Teachers in those districts with five years' experience are now earning between $67,000 and $74,000, compared to New London, where the pay is in the $40,000 range.

But Baez said it's not just the money.

"If someone is happy in the job, they don't leave, regardless of pay,'' he said.

There is uncertainty in job descriptions as the district moves to an all-magnet school concept, he said. And because of budget concerns, there is little job security.

Last April, the administration notified 75 nontenured teachers that their positions might be cut. After budget negotiations, all the jobs were saved and the notices rescinded, Fischer said.

But the district is now looking at another financial conundrum. Residents voted down the $39.8 million budget earlier this month and Fischer has asked all principals and department heads to list how cuts - from half a percent to 1.5 percent - would affect their budgets. A 1.5 percent cut to the budget is about $600,000.

Fischer said although the turnover this year is high, Cherese Chery, the district's human resources/talent officer, and Michael Fletcher, the Education Pioneer program recruiter, worked diligently to fill nearly all the vacancies. They contacted colleges and called around the country looking for teachers. The district has an electronic application system, which also expedited the process, he said, and a recruitment fair last spring attracted 250 candidates.

The Education Pioneer program, which is new this year, places those with non-education backgrounds in temporary administrative jobs in a school district. Funds for Fletcher's position come from the special master, Fischer said.

"Cherese and Michael have done a fabulous job of identifying candidates,'' Fischer said. "They've been proactive in trying to find people who fit the needs of our defined strategic operating plan."

The plan, adopted last spring, calls for New London to become an all-magnet school district, focusing on science and math, performing arts, and languages.

"The teachers we hired are outstanding. They're very high-energy and high-quality and really want to work in New London schools,'' he said. "Our goal is to get the best possible people in our classrooms to work with our students."

k.edgecomb@theday.com