In the past decade, seven people have led public schools in the District, four in Prince George's County and two in Montgomery County. Across the Potomac River, Loudoun County has had only one superintendent in that span.

As the Prince George's school board embarks on a search for a schools chief to succeed the departed Andre J. Hornsby, a major question is whether the person chosen to lead the system will have staying power, like Loudoun's Edgar B. Hatrick III, dean of Washington area superintendents.

Or will the new Prince George's chief, like so many other major school superintendents nationwide in recent years, be a transitional figure moving quickly through the revolving door?

Prince George's Board of Education members said yesterday that they want to hire a chief who will stick around for awhile.

"We're looking for somebody to continue and build on the academic policies we now have," said board member Charlene M. Dukes (Glenn Dale). "The motivation is . . . stability, consistency."

In an interview in Largo, Dukes and board Chairman Beatrice P. Tignor (Upper Marlboro) outlined the board's search plans in detail for the first time since Hornsby quit May 27 amid an FBI investigation and ethics controversy.

They said interim chief Howard A. Burnett, a veteran administrator with 30 years of experience in the system, would stay as long as needed for the board to pick a permanent successor. That will require an extension of Burnett's contract, which runs through Aug. 23, they said, and it will in all likelihood require him to stay longer than his stated goal of retiring by Oct. 1.

Dukes and Tignor said the board would advertise for a search consultant and pick one by mid-August. The consultant will help form a search committee, drawn from community activists, government officials and education experts, to advise the board. The search will seek national and local candidates and could last several months.

"We're looking for the best-quality candidate, and the length of time should not be a barrier," Tignor said.

However, Dukes said the board was mindful of the urgency of the search. "We want to move quickly, we want to move effectively, we want to be efficient," Dukes said.

Under state law, voters next year will choose a board to replace the current one, which was appointed in 2002 by the governor and county executive. The previous elected board was viewed as dysfunctional.

Dukes and Tignor said the current board rejected the scenario of leaving the choice of a permanent successor for Hornsby to a future board. Instead, they said, the board wants to offer a contract of at least two and as many as four years to its chosen finalist.

Hornsby lasted two years of a four-year pact that paid him $250,000 a year. He quit under a cloud, including a federal probe of his handling of certain contracts, but he has denied wrongdoing.

Before him, Iris T. Metts spent four stormy years as Prince George's superintendent and schools chief (the title changed to chief executive officer during her tenure). She weathered an attempt to fire her and left with a mixed record.

Before Metts, Jerome Clark served four years as superintendent, preceded by Edward M. Felegy, who also served four years. The last Prince George's school leader to serve more than four years was John A. Murphy. He held the job from 1984 to 1991 -- the year Loudoun hired Hatrick.

Across the country, school systems with urban populations and large numbers of low-income students have struggled to keep superintendents.

The Council of Great City Schools found that the average tenure of an urban superintendent in 2003 was less than three years. Fueling turnover are aggressive labor unions and newspapers, powerful corporations and fractured neighborhoods -- all at odds with one another over how to reform schools, said Michael Casserly, the group's executive director.

"The balancing act required in that kind of environment takes its toll," he said.

Experts said the high turnover hampers reform in school systems that most need it.

"You need at least five years to do the job," said Daniel A. Domenech, a highly regarded Fairfax County superintendent from 1997 to 2004 who is now an executive for McGraw-Hill Education, a New York-based publisher.

Often, Domenech said, urban superintendents are cashiered after a disappointing year in a troubled system. "People expect miracles, somebody to come in and show huge progress in one or two years," he said. "That's not realistic."