Generally speaking, and not in all instances, those schools that have higher percentages of students receiving special education services are going to tend to do less well on the tests. It's the nature of an education disability that it makes it more difficult for you to learn in some respect or another.
It's a time-consuming process. It would not be unusual to find most people do not want to do that indefinitely. It's also a process where the rewards are largely internal school board members get an inordinate share of the blame when things don't go well and very little of the credit when things do go well.