Eighteen months ago, the people of Rosemary Hills Elementary School were selected for an experiment in democracy: a chance to run a school as they wanted.

As one of nine places in Montgomery County picked to try "school-based management," the Silver Spring school got $10,000, formed a broad steering committee and debated ways to use its newfound freedom.

This spring, in a model of pure consensus, the school made a decision: to call the experiment quits.

"People were intrigued by the idea of having some kind of direct say," said Deborah Litt, a former PTA president who was the project's most active parent. "But it was an inexperienced group doing this. It was very time-consuming and very slow, and people just . . . lost steam."

In retreating from the experiment, Rosemary Hills has become apparently the first school in the Washington area and one of few in the nation to spurn an educational innovation that is gaining popularity among teachers, principals, parents and politicians. Several schools in Prince William and Prince George's counties are immersed in the new management method, and the District has received a $2.4 million grant to try the approach in nine schools.

The idea behind school-based management is to free schools from the bureaucratic regulation that typifies many public education systems. Working together, the theory goes, teachers, parents and administrators can devise the kind of education that suits their students best. Rosemary Hills was selected on the basis of a proposal to have teachers visit students' homes and revolutionize how children learn mathematics.

But as more schools try management-by-democracy, local educators and national experts predict that some will stumble for reasons that underlie the decision at Rosemary Hills. Those reasons include a shortage of time, uncertainty about what innovations to try, uneven participation and discomfort among parents and teachers with management powers traditionally reserved for principals.

"Superintendents all over the country are announcing, 'We will have restructuring,' " said Martin Carnow, an education and economics professor at Stanford University. "You can't go in there with wide-eyed, 'Dorothy from over the rainbow.' The question is, how long can they keep going? There will be a series of schools that burn out."

Jeffrey Martinez, Rosemary Hills' assistant principal, estimated the project took fully one-third of his working time. "Basically, education has traditionally been mandated by the school board and so on down the line," Martinez said. "It is hard to get around that."

Seth Goldberg, chairman of a school system committee overseeing the county's nine so-called flexibility projects, said the group is preparing to make recommendations this month on their future.

"We are not yet in a position to say {that} we have done an experiment and it works," said Goldberg, a school system psychologist. But, while the group is still honing its recommendations, he said the group plans to urge Montgomery School Superintendent Harry Pitt and the Board of Education to expand to more schools and to solidify their commitment through additional money and coaching.

Martinez and the school's teachers are sensitive that they could be regarded as a rare failure at a heralded educational reform. But Pitt, who embraced the two-year pilot project in 1988, said, "This is a chance to experiment . . . . I'm surprised that as many schools that started have stuck with it."

At least a few of the other schools have made decisions that already are changing children's education. At John F. Kennedy High School in Silver Spring, students are writing more in their English classes. At Twinbrook Elementary in Rockville, a kindergarten and a first-grade class have been essentially fused.

Still, Joy Frechtling, the school system's research director, said: "It is like baby steps. We are not yet seeing real change . . . stuff that couldn't have been done anyway."

Rosemary Hills was one of 25 schools that competed for the project's initial round. It is a diverse school near the District line, whose 575 pre-school through second-grade students form a kaleidoscope of nationalities and ethnic groups. Its magnet program, which was Montgomery's first, specializes in math, science, computers and classes for gifted children.

When the school was chosen "we didn't know that much about what this experiment was about," said Victor Exner, the computer teacher.

The school decided to form its steering committee and four subcommittees, to represent parents, administrators, nonprofessional staff members and teachers from each grade.

Parents also set up a representative assembly, whose leaders convened community meetings to explain the project and solicit ideas.

"As many people as there were, that is how many ideas were thrown out -- more physical education, homework, the playground -- all little things," recalled Ilene Sparber, the current PTA president.

"We had one guy who wanted to teach aerospace engineering," Martinez said. "We couldn't teach aerospace engineering. They wanted more recess time, but then half the group wanted less recess time."

"I don't think we really ever decided on anything basically because the school is satisfactory," said Litt, who was PTA president at the time.

By the start of the new school year last fall, Litt said, "I lost a certain amount of energy . . . . No one really stepped in to take it over."

Meanwhile, the idea of changing the math curriculum was dropped because the entire school system was starting a similar revision.

Teachers' initial enthusiasm for going into the community "was always a good idea but it wasn't a practical idea," Martinez said. The school decided on the less time-consuming alternative of a second parent-teacher conference.

Meanwhile, some of the committees faltered. One of them, intended to develop projects for the school "never really crystallized . . . . They spent a lot of time trying to find a chairperson," Martinez said.

In planning for the second conference with parents, teachers disagreed over when it should be held, Litt said. "The people who wanted it later in the year got very upset. People on the steering committee had a hard time accepting they would make decisions some people didn't like."

By this spring, the parents' group had grown relatively inert. Last month, when the steering committee circulated a questionnaire to guide plans for the coming year, the majority of teachers voted to restore management control to the principal, Linda Weber.

"I think people had a misperception of what shared decision-making is," Martinez said. "People thought their ideas would be acted on immediately. But there is a process. It isn't very fast."

Still, teachers and parents cite tangible accomplishments: the first thorough inventory of math books and equipment, more professional journals and teachers sent to more conferences.

The school has held lunchtime workshops, and a university professor is coaching teachers on creative math lessons.

The 18-month experiment "opened our eyes to being able to dare to use our creativity and the problem-solving skills that we teach our students," said Erin Johnson, a first-grade teacher on the steering committee.

Despite their decision, people at Rosemary Hills think that Montgomery should keep trying school-based management.

"I do think a lot of decisions would be better made at the school level," Litt said, "but it takes a real understanding of what is involved -- what you lose as well as what you gain."