Some Prince George's County school officials and local activists are wondering why county planners consistently have been unable to more accurately predict enrollment.

Those concerns were voiced when planners acknowledged last week that their latest five-year enrollment projections are faulty. The planners vowed to improve the accuracy by coming up with revised figures by the end of the month.

Tom Tyson, a county planner, told the park and planning department's commissioners at a meeting Thursday that education activists had "pointed out factors that will cause adjustments. In some areas, our figures may not accurately reflect development."

School officials and local activists have been complaining for years that the planning department's five-year projections are flawed. They worry that the inaccurate figures will lead officials to approve new permits for housing near crowded schools and allow the construction of new schools in the wrong places.

Tyson said planners will revise the numbers using more information about ongoing housing development and more detailed school boundary maps.

School board member Robert J. Callahan (Bowie) told the county park and planning board Thursday that school officials "want to know why each year we can't figure out how many students are in each school building."

County planners said the school system's desegregation plan led to complicated busing patterns that have made it difficult to predict enrollments, noting that thousands of students are bused across the county because of a 26-year-old desegregation order and that thousands more voluntarily attend magnet schools far from home. In addition, many families move into and out of the county each year.

Problems arise because county and school officials, who do their own projections, traditionally have not worked together to predict school populations.

In past years, school officials have not had access to county data on new housing developments. County officials, meanwhile, have had trouble understanding the school system's complicated boundary maps.

"We need to make sure the staffs of both organizations are working more closely together," Callahan said.

Three years ago, the county's park and planning division started developing its own school enrollment projections after county government leaders enacted legislation to control growth in areas with crowded schools. Under that measure, if enrollment at a school is projected to exceed 130 percent of capacity, local development is halted for four years.

Donna Beck and Linda Owens, two county activists who have monitored growth, pointed out some of the flaws in the projection to county planners in a meeting with them Wednesday afternoon.

Beck said that she is frustrated about the inability of the county and school system to work together to get the numbers right.

"I'm frustrated that it's clear it's not a team," she said. "The finger-pointing is getting in the way of progress. I don't intend to sit by quietly while park and planning looks for a scapegoat. If something is wrong with the numbers, it's on their watch."

Callahan said the problems in the latest projections might have been avoided had county planners consulted school system staff throughout the process and forwarded the projections to the school board before making them public Dec. 30.

"The Board of Education did not see that report," he said. "Any information in the future should be sent to the Board of Education."