By the numbers: the adult autism services gap in 7 charts

I used to think the argument for adult autism services was emotional. Then I started reading the federal data, and I realized the argument is arithmetic. The government counts autistic children carefully. It counts autistic adults badly. And it funds services for them as if the counting problem were a reason to wait.

The first three charts describe a population

Start with prevalence, because everything downstream depends on it. In 2000, the CDC’s Autism and Developmental Disabilities Monitoring Network identified autism in about 1 in 150 eight-year-olds. In the 2022 surveillance year, published in April 2025, that figure was 32.2 per 1,000, or roughly 1 in 31, across 16 monitoring sites.

Here is the part that gets skipped in every news cycle about rising prevalence. The eight-year-olds counted in 2000 turned thirty in 2022. The ones counted in 2010 are in their twenties right now. Every prevalence chart is also a forecast, and we have had that forecast for twenty-five years.

The second chart is the adult population itself. A CDC-affiliated estimate published in 2020 put the number of autistic adults in the United States at roughly 5.4 million. Not 5.4 million children who will one day be adults. Adults, now, today, most of them past the age where any entitlement applies to them.

The third chart is the one advocates argue about and families live with. In the Hughes analysis of ADDM data from 2000 through 2016, 26.7% of autistic eight-year-olds were classified as having profound autism, meaning nonverbal or minimally verbal, or an IQ below 50. Roughly one in four. Those are the adults who need staffed support for daily life, and they are the adults the current service system is worst at serving.

The next two charts describe what they receive

Chart four comes from the A.J. Drexel Autism Institute, published in The Milbank Quarterly in 2023. Between 2008 and 2016, only 1.1% of working-age autistic adults who likely needed employment services actually received them through either Medicaid or Vocational Rehabilitation. The researchers estimated 1.98 million autistic adults went without.

Read that as a percentage of the whole and it sounds like a rounding error. Read it as 1.98 million people and it sounds like a policy.

Chart five is the waiting list. KFF’s 2025 survey counted over 600,000 people on Medicaid home and community based services waiting or interest lists across 41 states. Not 600,000 requests. 600,000 people, most of whom have an intellectual or developmental disability.

The last two charts explain why nothing moves

Chart six is the wait itself. In the same KFF survey, people reached services after an average of 32 months. For people with intellectual and developmental disabilities specifically, the average was 37 months. In states that do not screen for waiver eligibility before adding people to the list, the average stretched to 49 months.

Three years. Four years. Say those numbers out loud next to the phrase “person-centered planning” and see how they sound together.

Chart seven is the quietest one and it explains the other six. The Interagency Autism Coordinating Committee tracks federal autism research spending by question area. Question 6 covers lifespan issues, which is where adult services, aging, and adult outcomes live. In 2019 and again in 2020, it drew 4.3% of total autism research funding. It was the smallest slice of the portfolio in both years.

We spend the research money on the beginning of autistic life and the service money on the beginning of autistic life, then act surprised when the middle and the end have no evidence base and no programs. That is not a mystery. That is a budget.

What the seven charts do together

Any one of these figures can be argued with. Prevalence estimates depend on ascertainment. Adult population estimates are modeled. Waiting list counts are, as KFF says every year, an incomplete picture of need.

Put them in sequence and the argument survives all of that. The population is large and documented. The share with high support needs is roughly a quarter. The share receiving employment support is roughly one percent. The wait for home and community based services runs three years or more. And the research that would tell us how to fix any of it gets four cents on the dollar.

None of that requires you to trust a single advocacy organization. Every figure in this post comes from the CDC, a federal advisory committee, a peer-reviewed journal, or a nonpartisan health policy foundation.

That is the whole point of a numbers post. When you sit across from a case manager or a legislative aide and say your adult child has waited three years, they hear one family. When you say the national average wait for people with intellectual and developmental disabilities is 37 months, and here is my family inside that average, they hear a system. Systems get budgets. Families get sympathy.

Your practical next steps

This week. Pick the one chart that describes your situation most exactly and find its primary source. Not the news write-up. The CDC report, the KFF survey page, the journal abstract. Save the PDF. You will use it more than once.

Next week. Write two sentences about your adult child. Name, age, what they need, how long you have waited. Put them above the figure in an email to your state representative and state senator, and ask for a written response. Then file the response, because a written non-answer from an elected official is itself evidence.

Seven charts will not get your kid a day program slot. But they will change what happens in the room when you ask for one. You stop being a parent with a complaint and start being a constituent with a citation. Same person. Very different meeting.