Are high special-education numbers related to poverty?

A disproportionate number of students from Maryland's lowest income districts are receiving special-education services, according to a recent review of state department of education data. Some say the numbers are higher in these areas because students come to school behind academically and in need of extra support, which sometimes can come only through special education. Officials from districts with lower numbers say early-intervention programming has helped them keep their numbers in check. The Washington Times/Capital News Service (12/20)  http://www.washingtontimes.com/news/2012/dec/20/more-special-ed-in-poorer-school-districts-of-mary//