Bryan Caplan  

The Puzzling Ubiquity of Disability

The Key to victory: Run agains... Zeke Emmanuel on Optimal Life ...
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.

Comments and Sharing

COMMENTS (21 to date)
Greg Robbins writes:

I used to substitute teach in Burbank, California. Students there were put in special education classes if they had bad behavior in class. They would be put in a class with kids that were retarded, and they'd all do second grade math while attending high school. There were no standards to qualify them for graduation, and most of them were quite illiterate. I've heard that the parents also got more money from the state if their kids went into a special ed class. Once a kid went into special ed, he or she never got out of the program.

Mark V Anderson writes:

I am somewhat skeptical of the argument that schools put kids in special ed because of the financial benefits the schools get. I am always hearing schools pleading poverty because they claim that the state has all sorts of mandates without providing financial support. Sure many of those complaining are professional whiners that will look for any reason to clamor for more state support. But I do detect at least some sincerity in their complaints, so I don't think the schools will purposefully put kids in special ed to collect more funds. Even if Greene and Forster are correct that schools collect more than they spend, that is immaterial for this argument if the schools don't think so. Admittedly, I have no data to back this up.

I think the increase in disability is due to the nature of society we are growing in this country. There are many more professionals looking for students to classify as disabled, so they can medicalize a problem they can't explain any other way. There are also plenty of parents looking for an excuse for their kids' lack of success, so are happy to have an excuse for their kids doing poorly. And to be fair, there is some reversal of the previous American principle of never accepting that one's kid is disabled. Some of these kids that were previously not labeled as disabled really were. Again, I have no data on this, but this is my impression.

Brian writes:

1. If you can get diagnosed with a learning disability, you can get popular drugs that are illegal for other students to use.

Some of them keep you docile for your parents and teachers so that they don't have to constantly clean up after your rambunctiousness, like Ritalin.

Some of them are good for studying hard and keeping focus so that you can strive to compete with the other grindy striver kids. We used to use coffee and caffeine for this but amphetamines like Adderall (dextro-amphetamine or dexadrine) and Desoxyn (methamphetamine) are really effective. And they're cheap with a prescription and totally not dangerous -- the main danger with drugs is getting arrested and you're 100% immune.

2. If you can get diagnosed with a disability, you can demand extra time on tests and projects. Would you like 75 free points on the SAT? How about a chance to think and write longer and more carefully on that history or calculus exam? Just get a learning disability diagnosis.

The SAT people have to give you extra time by law and they can't even print on your score report that your score was 'earned' under different circumstances than the poor kids' whose parents didn't get them a doctor who would diagnose a disability.

The same applies to tests in your school, giving you a big advantage in GPA.

Really, and responsible parent should be getting his children diagnosed. It's not hard to qualify for something with the vague and subjective standards that apply nowadays.

And adults with diagnoses can start collecting Social Security at age eighteen while the rest of us pay in to support them. Used to be 80% of SSD recipients had heart or lung failure, now they're mostly people who are uncomfortable reading or easily distracted.

Douglas writes:


That drop also had to do with the downward redefinition of mental retardation that took place during that period:

"The threshold I.Q. level for a diagnosis of mental retardation has been progressively lowered over the years, in part because of awareness of the damaging social prejudice suffered by those labeled 'retarded.' In 1959, the American Association on Mental Deficiency set 85 as the I.Q. below which a person was considered to be retarded. In 1992, the renamed American Association on Mental Retardation lowered the mental retardation 'ceiling' to an I.Q. of 70-75..."
Joe writes:

The way learning disabilities are treated strikes me as further evidence for the signaling model of education.

That is, through total exemption or increased time or what have you "learning disabled" people get to opt out of certain skills they'd otherwise be required to learn, and continue on in their lives, getting jobs and interests that don't require time pressure, or foreign language or what have you.

If it was the skills that were important, you would think the learning disabled kids would always be given extra tutoring and worked *harder* so that they would also acquire the skills.

Anecdotally, when i graduated high school ~3 years ago, tons of kids would look up and read the ADD test so they could get the "right" answers when they asked their doctor for a prescription. Not to mention the rampant cheating, high school was a den of thieves, I often wonder if being socialized in such an environment increases cheating on a societal level.

Yaakov writes:

I can write a little about the experience in Israel.

According to the following article in Hebrew:

from over 1.9 million students, about 160,000 are designated as special needs students. About 73,000 learn in special classes or even special schools, while the remaining 87,000 learn in regular classes. The state comptroller has criticized the fact that the percentage of special needs students in regular classes has gone down. The reason is that the big money incentives are given only to the students in separate classes or schools, while special needs children in regular classes get very little funding. This policy works well in limiting the budget on special needs students, as parents are very reluctant to send their children to special classes or schools, if not totally necessary. On the other hand, sending students to special education is one of the only ways to get disruptive children out of the class. The following article:
raises the question of whether second generation Ethiopian Jews, considered a weak social group, are being sent to special education classes due to their lower reading and writing pre-school abilities. The numbers show that about 16% are sent to special education, double the percentage in the general public.

I several years ago read an article that pointed out that the percentage of students with the lighter disabilities, allowing extra time on tests and other such benefits, is much higher in wealthier neighborhoods. I believe the numbers were above 20%. I think these students do not qualify as "disabled".

Miguel Madeira writes:


I don't know how is in the US, but in Portugal the main accomodation for students with ADHD/ADD is extra time in tests; "making a test in a specific period of time" is not supposed to be a skill that schools will teach - it is supposed to be only a way of measure the real skills acquired (knowledge of Mathematics, History, etc.).

In the case of studentes with specific learning disabilities (for example, in a specifical subject, like Math), the tipical "help" is to have additional classes.

Both things are perfectable compatible with the human capital model (if anything, it is the signalling model that is contraditory with the accomodations to students with specific problems - if the point of school is not teach things, but signalling that you have some qualitys like intelligence or working under pressure, it is the extra classes or the additional time in tests that don't make sense)

Shane L writes:

The first thing I thought was that modern schools are probably better designed for people with disabilities. If a child is in a wheelchair and the school has no wheelchair ramps the child has great difficulty attending. Might some children have been forced out of the system in the 1970s because the infrastructure wasn't there to support them?

Rebecca writes:

The authors think they have disproved the "real incidence" theory because they point to a decrease in mental retardation and other "severe disabilities." But what categories of special education disabilities have increased? I think no exploration of this issue can be said to be thorough without a discussion of the rise of autism and learning disabilities like dyslexia and ADHD. Forty years ago, many of those children might have been labeled mentally retarded instead of the more socially acceptable diagnoses that are used today. Or they would have simply been kids who got bad grades, without their disability ever being identified and treated or controlled for.

Pointing to the differences in incidence between states that determine funding by the two methods doesn't prove that states that place a premium on additional diagnoses are over-identifying disabilities. It might instead be discouraging diagnosing actual disabilities in those schools which know that they will then have to stretch their funds further with no additional help from the state that mandates the services.

Jeff writes:

If you're really interested, you may want to look at some other research, such as from IOM (here and here).

For information on the trends in childhood disabilities see here .

One other thing to keep in mind is that there is far less stigma associated with mental illness now than in prior years, potentially changing reporting. Coupled with greater identification of some disabilities (e.g., autism), you would expect more.

As for extra time on the SATs, well, that is not really what is on a parent's mind at ages 2 to 4 when their kid is getting tested for falling behind on all the developmental milestones. So you might not want to use that argument. Ever. Parents are not that forward thinking, by and large.

Miguel Madeira writes:

I wonder if things like "pre-school", "day care", etc. could be contibuting to more "disability" - my point: some behavioural "excentricities" could be only "excentricities" if you spend most of your time with your family or with your street/block friends, but can became a "disability" when you spend most of your time in a regimented/hyper-socialized environment, with less tolerance to individual peculiarities.

Sol writes:

My son just started in the local school district's special education kindergarten, so let me give my perspective on this.

My son has Asperger's. In some ways he is almost painfully smart. In others, his behavior is closer to a 2 year old's than his actual age of 6. Last year the school district gave him an intelligence test with five sections on it. His scores for the various sections ranged literally from the 0th percentile to the 99th. His social skills are atrociously bad; he has been thrown out of three preschools for bad behavior.

The special ed program is exactly the right place for him. Put in a normal classroom right now, he would be terribly disruptive and probably learn little. In the special ed classroom, he gets to work with people to help improve his behavior every day and he gets the individualized instruction he needs to bring out what he is capable of. I have little doubt that he will be reading by the end of the school year.

Historically, I don't think the system was at all good at recognizing issues like this. I remember one kid from my middle school that was smart, extremely weird, and had terrible behavior. I strongly suspect he was an undiagnosed case of something like Asperger's.

Likewise it doesn't surprise me in the least that these things are more commonly diagnosed in wealthier areas. This had my wife and me (late 30s & early 40s, both with master's degrees) and my preschool teacher mother-in-law baffled for years, and eventually a therapist baffled too. Once we finally started figuring things out, we went through a period of several months where we probably averaged 4 hours a week of doctor's visits and tests. It would hardly be surprising if the children of poor 20-year-old single moms were more likely to fall through the cracks...

RPLong writes:

+1 on Rebecca's point. I don't think the authors adequately accounted for all the relevant factors here.

magilson writes:

One of my parents is an ED/LD teacher and has been for over three decades now. The majority of what I hear vented about is that the number of children with behavior problems (generally severe and the vast majority of the population of the classes; as opposed to a normal distribution of ED and LD of varying severity) that simply cannot possibly sit in a normal classroom environment and learn as our Federal/State education system requires. A large majority of time is spent simply teaching basic life skills, manners, and hygiene that should have been delivered by the child's guardians. I've heard these stories all my life at each grade level my parent has taught which now includes elementary through to high school.

The 13% doesn't surprise me even slightly. And while I would agree it's not due to genetic retardation or some other "traditional" cognitive issue I think it's real. I would say my impression is that it has more to due with the child-rearing choices of an increasing number of parents as well as their consumption choices during pregnancy.

I don't disagree with the premise of the "Special Ed needs money". All I'm saying is in my perspective of the tiny corner of the education universe I know is that it sure doesn't sound like they're stacking the deck against these children. The children are in these programs for good reason.

Colin Barnard writes:

I think the authors have missed the most important factor.

If a child is deemed "disabled" what happens in the classroom? Either the child is removed and put in special ed or an educational assistant is added to the classroom. Who benefits from that? The teacher.

Who is most likely to call for an assessment of a child? The teacher.

I'm not an economics expert, but if something has no cost and only benefits...

Another Jeff writes:

I was going to say the same thing as Rebecca: real incidence of disability may not have declined the way the authors believe, as they seem to be overlooking the higher rates of autism among kids today. Not sure what the statistical impact of that would be, as compared to the decline in Down Syndrome kids, but it definitely bears mentioning.

On the other hand, I'm not sure on this but I think there are fewer kids with hearing problems who wind up in special ed these days, as the technology available to help them has gotten a lot better over the last thirty years or so.

Tom West writes:

Why use the past as the benchmark on which to judge the present?

Wouldn't a more sensible approach be to research why in the past rates of diagnosis were way below actual rates of disability?

More sensibly, it's obvious (to me at least) that diagnoses will increase as resources available to treat increase. Of course, returns to treatment decrease as less severe cases fall under diagnosis, but claiming any one point on the curve is "correct" is silly.

As a society, we simply have to choose where we make the trade-off resources vs. improving the lives of people with disabilities.

NZ writes:

I'm inclined to think real incidences have indeed gone way up. The number given actually seems low.

In the last several decades it has become much easier for people with real mental retardation to blend in, seem more normal, and reproduce. (Our dumbed-down culture has met them half way, too. Can you distinguish between a socially fashionable person and a retarded person? I wouldn't count on it.) Also, there's the Idiocracy effect, with low IQ people having way more kids and high IQ people increasingly having fewer.

Joe writes:


I'd say If a time limit is required to measure skills required, then that calls into question the measuring of those who can only perform when given double time, logically their skills wouldn't be measured correctly.

Though, I suspect time limits are a good way to quickly create a bell curve for kids to signal on, rather then actually being necessary to measure skill.

Of course your right, when you say getting extra time would be a terrible signals. If schools SAW that the kid got extra time, it would screw him/her over and signal academic weakness, but that fact is generally hidden on their transcript. at least in the U.S. Thus they get the signaling without the performance.

KLO writes:

The single most reliable trend data on childhood disability comes from birth weight figures, because low and very low birth weight is very strongly correlated with disability and because birth weight is objectively measured for every infant. According to the CDC the proportion of infants with low birthweight increased over 11% between 1980 and 2000. The proportion of infants with very low birthweight increased over 24% during that same time. These figures strongly suggest a rise in disability, particularly in the significant disability category.

Mark Bahner writes:

That's surprising to me. Why would the proportion of infants with very low birth weight increase so dramatically? I would think mothers would be getting better care in 2000 than in 1980...

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