In the last three decades, special-education programs in the United States have grown at a tremendous pace. Much of this growth reflects a growing incidence of students diagnosed with the mildest form of learning disability, called a Specific Learning Disability (SLD), and thus the hardest to distinguish from an ordinary cognitive deficit. Between 1977 and 2006, the proportion of public school students diagnosed with SLD trebled, from 1.8 percent to 5.6 percent. By the end of that period, 40.7 percent of all students enrolled in special education had been identified as having an SLD. A limited but growing body of research suggests that financial and other incentives may be responsible for a portion of these increases.
The question examined in this report is whether special-education voucher programs change the likelihood that students will be diagnosed with an SLD. Voucher programs allow disabled students to attend a private school, which receives payments in the form of full or partial tuition that would have otherwise been directed to the transferring studentâ€™s public school. Special-education voucher programs appear to reduce a local public schoolâ€™s financial incentive to diagnose a marginal student who is merely struggling academically as suffering from an SLD by offering him the chance to leave the public school, enter a private school, and take all of his funding with him.
Four statesâ€”Florida, Georgia, Ohio, and Utahâ€”have these programs. They are the fastest-growing type of school voucher program nationwide. We made Floridaâ€™s, the first of them, the focus of our research.
It has been argued that voucher programs cause nominal disability rates to increase because parents with a preference for private education lobby to have their child diagnosed with SLD. If parental pressure was the factor responsible for skyrocketing rates of disability classification, we would expect the introduction of a voucher program to accelerate this trend. We find, however, that fourth- through sixth-grade students in public schools with an average opportunity to participate in Floridaâ€™s special-education voucher program during the 2005-06 school year, based on the relative proximity of private schools willing to accept the vouchers, were about 15 percent less likely to be newly diagnosed with an SLD than they would have been in absence of the program. This finding points to another explanationâ€”namely, the link found by prior research between financial incentives and the rate at which students were designated as disabled.
We contend that the reduction in SLD classification observed in the Florida schools after the introduction of a voucher program results from denying public schools what they understand to be the economic benefit of receiving a supplemental payment from the state for every additional child designated as suffering from an SLD. Thus, special-education vouchers appear to constrain costly growth in special-education enrollments.