Setting the annual budget for the Plainville and King Phillip school districts is never easy. And the struggle to find the money is compounded by the rising number of special-needs students.

Although state law requires programs for their education, state funding for those mandates is falling behind.

"We have to decide where we are going to channel the money," said Charlene McEntee, a member of the Plainville School Committee. "We try to treat everybody equal, but sometimes it's difficult. It is an agonizing decision to make."

To remedy the growing gap, state Rep. Richard Ross, R-Wrentham, filed a bill last October to increase special education funds.

"The school districts of the commonwealth deserve to be reimbursed for the actual special-needs population that they serve, not an arbitrary number that fails to address the needs of all students," Ross said. The current funding formula for special education is based on a fixed percentage that is supposed to reflect the number of enrolled students. But the gap between this "artificial" cap and the real numbers is growing.

Last year, 121 students out of 847, or 14 percent of students enrolled in Plainville schools had learning disabilities. But the district only received state funds to pay for the education of 29 special education students.

That's because funding is based on an enrollment number set at 3.75 percent for in-districts students, and 1 percent for out-of-districts students. The formula does not allow schools to count for the actual number of special education students enrolled.

The formula was adopted in 1993 as part of the Education Reform Act. When it was first established, the percentages were 3.5 percent for in-district students and 1 percent for out-of district.

The only increase was in 2002, and set the current percentages.

"We need to take an look at the funding formula and start looking at the real numbers," Ross said.

Besides the financial aspect, the current situation creates tensions.

"Since school districts are required to provide these services, the funding problem moves to the local level," said Mike Gilbert, field director with the Massachusetts Association of School Committees. "Districts are forced to squeeze other services to provide special education services."

And for some people, it is not acceptable that special education funding undermines regular education.

"They don't really understand the dynamics of the issue, and for them it's 'Those kids who are taking away the education money for my kids'," Ross said. Ross said he hopes that changing the system will ease the tensions.

"Things that have to be switched away from regular education create a rip between people who are advocating for one group of children, and those advocating for another," he said.

Ross proposes to replace the current formula with a more realistic plan that would base the percentage on the average number of enrolled special education students over five years.

For example, in the past five years, the percentage of special education students in Norton schools would have been 18.7 percent of the total population; in Plainville, it would have been 12.9 percent; and 16 percent for the state, instead of the current 3.75 percent.

The original formula was supposed to reduce the number of special education students because of the belief at that time that a significant number of students were wrongly classified as special needs, Gilbert said.

"Time and data have proven this was not the case," he said.

Numbers also changed. In the past five years, the number of special education students has increased.

The percentage of students enrolled in special education has increased from 15.3 percent in 2002-2003 to 16.9 percent last year. In Norfolk, such students represented 13.3 percent of the student body. Today, they represent more than 20 percent.

In 1993, the Foundation Budget Review Commission was created. It was supposed to review enrollment figures and file recommendations to the Legislature concerning funding formulas for special and regular education.

It gave its last report in 2001. Since then, the number of special education students hasn't been reported.

"Until we take a look at the number, it is a little hard to assess," Ross said. "It is a big number but nobody really knows how big."