Forty-four D.C. public schools -- about a third of the schools in the system -- will have a new principal when classes start next week, Superintendent Clifford B. Janey announced yesterday.

School officials said the turnover is unprecedented and reflects a high number of retirements and an effort to weed out principals who were not performing adequately. Janey had said in April that 25 percent to 40 percent of the system's principals were not up to par.

"These principals come here prepared to make good on our public promise" to improve student achievement, Janey said at a news conference at Gallaudet University attended by the new school leaders. "I think they know precisely what is expected of them."

Of the 44 appointments, 23 are people hired from other school systems or an outside principal training program called New Leaders for New Schools.

The number of vacancies was about twice as high as last year, officials said. Six of the openings resulted from resignations, six from dismissals, 13 from retirements and the remainder from promotions or leaves of absence, Janey said.

School officials also emphasized that unlike previous years, all principal vacancies have been filled before the start of the school year.

"It's comforting to know we can start the school year with the staff in place," said Tony Demasi, executive director of the system's human resources department. "This is my fourth year here and the first time we've offered the jobs as early as we did."

School system officials said they started recruiting for principals and teachers earlier than usual to reduce the number of strong candidates they typically lose to other districts. They also wanted new principals and teachers in place early enough to prepare for next week's launch of new learning standards, textbooks and curricula.

The Council of School Officers, the union that represents D.C. principals, has filed grievances on behalf of several principals whose contracts were not renewed, alleging that they were not given adequate warning that central administrators were unhappy with their performance. Nevertheless, the council's president, Bernard C. Lucas Sr., said he was generally pleased that the school system moved quickly to fill vacancies.

"We're satisfied that the appointments were made in a timely manner, which affords the principals time to plan and get their staffing in place," Lucas said.

Demasi said the school system has hired 414 new teachers, leaving about 112 vacancies. More than 100 of the teachers were hired from organizations, such as Teach for America, that recruit for urban school systems.

In April, Janey had said about 1,400 teachers lacked required credentials. Demasi said yesterday that the number has fallen to about 800 and that he expects all teachers to be fully certified by June 2006.

Nathan Saunders, vice president of the Washington Teachers' Union, said the system is doing a much better job hiring this year. "Historically, the District was making hiring decisions as late as mid- to late August," Saunders said. "This year, they did the bulk of the hiring in June, which is great."

But he said the number of vacancies remains high and demonstrates a high level of teacher dissatisfaction. "The District does a very good job of turning off teachers," Saunders said. "They get frustrated and opt to look for professional opportunities elsewhere."

In the recruitment of principals, Meria J. Carstarphen, the system's chief accountability officer, said she and her staff were deliberate in finding the school best suited for each candidate. She said they also sought to assemble a team that could help principals at 81 schools identified as "in need of improvement" for failing to make academic benchmarks two or three consecutive years under the federal No Child Left Behind law.

"For the restructuring and corrective-action schools, we want to put together the right supports to help those principals succeed," she said.

At the news conference, several new principals explained why they sought jobs in the system.

"I wanted to become involved in a school district making changes in terms of its approach to children . . . and professional development for teachers and principals," said Carol Barbour, principal of Rudolph Elementary School in Northwest and a former principal in Prince George's County. "I started July 1, and it's been a pleasure to work here each day."

Diane Powell, assistant superintendent for support services, relays information to new principals at a meeting at Gallaudet University.