A growing number of students in public schools—right now, about 15% of them—are eligible for special education services. These services include specially designed instruction for students with autism, learning or physical disabilities, or traumatic brain injuries. But going into the current school year, more than half of U.S. public schools anticipate being short-staffed in special education. Dr. Kimber Wilkerson, a professor of special education and department chair at the University of Wisconsin-Madison, explains why there's a shortage and what needs to be done to close the gap.