The cost of special education in Massachusetts school districts is soaring and now amounts to 20% of school budgets statewide. The cost of programs for students with severe disabilities and reduced federal and state funding have all contributed to the higher expenses, which come at a time when many districts are facing financial crises. "Children deserve these services, and we're required to provide them," one superintendent said. "The problem is that these services are expensive. We're given responsibility but not given the resources."