The Puzzling Ubiquity of Disability
By Bryan Caplan
In 1976, 8.3% of students in U.S. public schools were officially disabled. By 2010, the disabled share was up to 13%. What on earth happened? This piece by Jay Greene and Greg Forster considers and critiques three main stories. Prepare to be edified:
At least three different culprits have been identified: greater real incidence of disabilities, the advent of high-stakes testing, and the financial incentives created by special education funding.
What’s wrong with the “real incidence” story?
Defenders of the U.S. special education system argue that the growth of enrollment in special education reflects growth in the real incidence of disabilities in children. According to this explanation, there are simply more disabled students than there used to be, and those students have more costly disabilities… They attribute this alleged growth in student disabilities to social forces over which schools have no control, pointing to three factors in particular: improvements in medical technology, deinstitutionalization of children with serious difficulties, and increases in childhood poverty…
However, this account is not consistent with the facts. The authors argue that there are now more children with mental retardation because improved medicine saves more low-birth-weight babies. While it is true that the number of such babies expected to exhibit retardation has grown, the actual number of students classified as mentally retarded has dropped remarkably– from about 961,000 in 1976-77 to about 599,000 in 2000-01… As a general matter, while medical improvements will certainly cause some number of children to survive with disabilities where in a previous era they would have died, it will also cause other children to avoid developing disabilities where in a previous era they would have become disabled. From improved prenatal medicine to safer child car seats to reductions in exposure to lead paint, medical improvements have saved untold thousands of children from disabilities.
Furthermore, the decline in the number of students with mental retardation, as well as those with other severe types of disability, also disproves the argument that deinstitutionalization of students with severe problems is driving increases in special education enrollment. As for childhood poverty, it hasn’t actually increased. For children under 6, it was 17.7% in 1976 when federal law first required special services for disabled students, and it was 16.9% in 2000.
Greene and Forster could have further strengthened their case by pointing out the rising role of selective abortion: This meta-analysis estimates that Americans abort 67% of detected Downs fetuses.
How about the other stories?
Why would schools place more students in special education when they didn’t truly need it? Some researchers are now identifying high-stakes testing as a possible cause. More and more states have adopted test-based accountability programs in which significant consequences, such as student promotion and graduation or school funding cuts, are attached to performance on a standardized test… But these programs can also create a perverse incentive: an incentive to game the system by getting low-performing students out of the testing pool altogether. By labeling such students as disabled and placing them in special education, schools can exempt them from mandatory testing.
Despite its intuitive appeal, Greene and Forster finds little support for this explanation. But another incentive-based story looks very strong indeed:
School districts have traditionally received state funding for special education, which makes up the bulk of all special education funding, in such a manner that they receive more money if their special education programs are larger. This provides school districts with a financial reward–a bounty, so to speak–for placing students in special education. Critics of the U.S. special education system have long argued that this creates a perverse
financial incentive to put as many students as possible into special education. Defenders of the system often argue that funding for special education cannot create perverse incentives because placing a student in special education creates costs at least equal to the new funding it generates. This misrepresents what truly is and is not a “cost” of placing a child in special education. A true cost is an expenditure that the school would not have made otherwise. Some services that a school would have provided to a particular child no matter what can be redefined as special education services if the child is placed in special education; these services are not truly special education costs because they would have been provided anyway. For example, if a school provides extra reading help to students who are falling behind in reading, the school must bear that cost itself. But if the same school redefines those students as learning disabled rather than slow readers, state and federal government will help pick up the tab for those services. This is financially advantageous for the school because it brings in new state and federal funding to cover “costs” that the school would have had to pay for anyway.
The only obvious problem with Greene and Forster is that it’s over a decade old. Question for readers: What relevant evidence has emerged since 2002, and what does it say? Please show your work.