In the past two years, nearly 100 changes in principals have occurred at D.C. public schools, an extraordinary turnover rate that local educators and parent activists cite as a prime reason academic work in city classrooms is not improving.

Some of the changes in the school system have been made to replace retirees, but many principals have been ousted, transferred or demoted, according to a Washington Post review of school records since August 1988, when Andrew E. Jenkins became superintendent.

The shuffle of principals, records show, has occurred most often in the city's poorest neighborhoods, where student achievement is lowest. In Ward 8, which includes communities southeast of the Anacostia River, principals at 17 of 23 schools have been changed since fall 1988 -- some two or three times.

Records also show that in some cases, principals apparently removed from one job because of poor work have been given the same job at schools in other parts of the city. Few principals being moved leave the system; and only one of the 99 changes involved hiring an outsider.

"This is causing tremendous disruption. We have no continuity," said Addie Hargove-Butler, PTA president at Petworth Elementary School in Northwest, which has had four principals since last fall.

Parent leaders and school officials say some changes have helped schools, and that turnover had been a problem for years before Jenkins took charge. Yet there is growing concern that moves are being made too abruptly, often at the whim of a school board member and without notifying teachers or PTAs.

"There have been more moves in the last two years than there has been in a long time," said William Simons, president of the Washington Teachers Union. "That doesn't bode well for the system. All the changes aren't bad, but it's very unusual to have so many switches."

Jenkins said he does not believe the changes have hurt faculty morale or classroom progress.

Instead, he suggested that the changes show he runs a tight ship, with principals held more responsible for student performance. "We don't do this capriciously or cavalierly," Jenkins said. "We do it to strengthen a school's educational program. For too long, we have allowed situations to exist at some schools and we didn't do anything."

Jenkins also defended instances in which principals were moved from one struggling school to another, saying that "at times all that's needed is a different setting for a principal to excel."

Last year, Douglass Junior High School in Southeast had three principals. Jenkins's eventual choice, James Campbell, had been a principal at three other D.C. schools, including a stint at Coolidge High that ended when the D.C. auditor found financial improprieties there.

This fall, Jenkins removed Principal Isaac Jackson from one of the system's most troubled schools, Moten Elementary in Southeast. Jenkins said Moten "needed new direction." He appointed as principal Sandra Coates, whom he removed as principal of Malcolm X Elementary last spring after parents alleged she was selling junk food to the students and not accounting for how profits were spent.

And Jackson now is principal of Weatherless Elementary, which this year posted some of the lowest student test scores in the city.

Meanwhile, Petworth has had two principals since August. The first, Michael Hammond, had been principal at Beers Elementary until he was removed this summer. He was sent briefly to Weatherless before Jackson, then to Petworth, then to a job in the system's athletic department -- all in the three weeks before classes began.

In the time Hammond spent at Petworth, the system transferred the school's clerical assistant and replaced her with an aide Hammond had at Beers. That enraged the Petworth PTA. "Suddenly we had no one in the office who could work the data system," said Hargrove-Butler, the PTA president. "We couldn't order any supplies." When Hammond left, parents got the school's first clerk back and finally ordered supplies.

The rate of change among District principals exceeds the rate found in the area's suburban school systems. Since fall 1988, more than half of the principal positions in the city's 175 elementary and secondary schools have changed hands.

This fall, there were nearly three dozen moves. In Prince George's County, which has 171 schools, there were 12. In Montgomery County, which has 172 schools, officials said there were fewer than 20 changes this year.

Educators locally and nationally have little doubt that schools sink or swim on a principal's leadership. Across the country, school bureaucracies are shifting more authority to principals and boosting their salaries. A principal organizes a school's staff and its PTA, its classes and its budget.

As in most school systems, the D.C. superintendent nominates principals and the school board appoints them. They serve three-year terms. But Jenkins -- and in more subtle ways, the board -- have wide latitude to end that term whenever they see fit.

Parents and union leaders are questioning many of Jenkins's moves, saying that at times he seems to be doing little more than rotating principals. The changes, critics say, have left many principals fearful of any misstep. Dozens of them have spent more than a year with the title "acting principal," awaiting approval.

"There's a lot of insecurity," said one veteran principal who asked not be identified. "Principals know they have to be on the good side of a board member, so that means you don't always make educationally sound decisions."

There is great suspicion -- but little proof -- that the board plays a large role in many decisions. Jenkins denies it, but union officials and several school board members said they believe that once a principal falls from a board member's grace, a change is imminent.

In recent interviews, five school board members said removals often are due to board pressure on Jenkins -- but each of them said they did not do it. "Politics has a lot to do with it, and it has a demoralizing effect on principals," said board member Wilma R. Harvey (Ward 1).

"The board has made these jobs political appointments," said Frank Bolden, president of the Council of School Officers, which represents D.C. principals.

Bolden and others target much of their ire at Ward 8 school board member R. Calvin Lockridge. During the past two years, there have been more changes in his ward than in Wards 2, 3 and 6 combined. Bolden accuses Lockridge, one of Jenkins's few allies, of using Jenkins to appoint whomever he wants.

Lockridge said he neither has nor wants that influence. But he said he is pleased with most of the 24 changes Jenkins has made in Ward 8. "I know the principals union is hollering, but this isn't disruptive. We're making changes for the better."

Though changes in Ward 8 outnumber other wards, the moves usually reflect a citywide pattern: A longtime school system insider is selected, and often the choice is not so much a promotion of a potential star as it is a second or third chance for a principal to succeed.

School system leaders complain that some of their best principals have been lured to suburban schools for more money. But records show that since fall 1988 only one, Michael Durso of Wilson High School, has left the city to work in the suburbs.

"The system has become closed; it does not reach outside for fresh faces," said board member R. David Hall (Ward 2).

But Jenkins, who has been told by the board that his contract will not be renewed when it expires next summer, is undaunted.

"Philosophically, I believe this kind of change is necessary," he said.

"I would imagine that some principals see it as a reason to be insecure, but they shouldn't." Jenkins said. "It's more of an accountability aspect than anything else."