Improper Medicaid autism-therapy payments: $197.9M in four states
Summary
Applied Behavior Analysis, a therapy for autism, has seen its Medicaid billing grow sharply in at least one state: Colorado's fee-for-service ABA payments rose from $60.1 million in 2019 to $230.3 million in 2024, nearly quadrupling in five years. HHS's inspector general is auditing states' ABA billing in an ongoing series. In Colorado and Maine -- the two audits read in full -- all 100 sampled enrollee-months in each state included a claim line that was improper or potentially improper. OIG estimates Colorado made $77.8 million in improper payments and Maine $45.6 million; combined with earlier findings in Indiana ($56 million) and Wisconsin ($18.5 million), the four-state total stands at $197.9 million. The most common problems: missing or incomplete session notes, care that couldn't be verified as therapy at all, and -- in Colorado -- providers with no requirement to hold the credential the state's own insurance law requires for children on private insurance.
A therapy Medicaid spending quadrupled to catch up to
In July 2014, clarified that state Medicaid programs must cover diagnosis and treatment -- which may include ABA -- for children with autism, folding it into the Early and Periodic Screening, Diagnostic, and Treatment (EPSDT) benefit that covers medically necessary pediatric care. Colorado's ABA spending⧉ shows what followed: fee-for-service payments were $60.1 million in 2019, more than doubled to $163.5 million by 2023, and reached $230.3 million in 2024 -- growth 's report notes has drawn attention from federal and state agencies to questionable billing patterns among some providers.
View data as table
| 2019 | 60.1 |
|---|---|
| 2023 | 163.5 |
| 2024 | 230.3 |
Every sampled month, something wrong
's audits sample enrollee-months and extrapolate to the full population. In Colorado, all 100 sampled months included at least one improper or potentially improper claim line; estimated $77.8 million in confirmed improper payments ($42.6 million federal share) and a further $207.4 million in payments it could not fully verify. Maine's audit⧉ of its rehabilitative and community support services -- which include ABA -- found the identical pattern: all 100 sampled months flagged, with an estimated $45.6 million in improper payments ($28.7 million federal share). Two earlier reports in the same series found $56 million improper in Indiana and $18.5 million in Wisconsin.
View data as table
| Colorado | 77.8 |
|---|---|
| Indiana | 56 |
| Maine | 45.6 |
| Wisconsin | 18.5 |
What actually went wrong
In Colorado, 93 of 100 sampled months had documentation requirements not met, 18 involved staff lacking appropriate credentials, and 7 had no diagnosis or treatment referral on file at all. Among payments could not confirm as proper or improper, 96 months had session notes that didn't fully describe the services provided, 88 involved potentially unallowable activities, 76 showed potential nontherapy time billed as treatment, and 67 involved group activities billed as individual care.
View data as table
| Services not fully described | 96 | potentially improper |
|---|---|---|
| Documentation requirements not met | 93 | improper |
| Potential unallowable activities or care | 88 | potentially improper |
| Potential nontherapy time | 76 | potentially improper |
| Potential group activities | 67 | potentially improper |
| No appropriate credentials | 18 | improper |
| No diagnosis or treatment referral | 7 | improper |
Maine's breakdown ran similar: 81 of 100 months had a missing comprehensive assessment or missing required signatures, 64 had session notes that didn't meet documentation requirements, 30 had treatment-plan defects, and 20 involved providers without required credentials. On the unverifiable side, 94 months had incomplete session-note descriptions, 92 showed potential non-therapy time, and 34 referenced potentially unallowable recreational or academic activities.
View data as table
| Session notes incomplete descriptions | 94 | potentially improper |
|---|---|---|
| Non-therapy time | 92 | potentially improper |
| Missing assessment or signatures | 81 | improper |
| Session notes lacked documentation | 64 | improper |
| Unallowable recreational/academic activities | 34 | potentially improper |
| Treatment plan issues | 30 | improper |
| No provider credentials | 20 | improper |
A credentialing gap Colorado didn't close
One finding stands out structurally rather than as a documentation lapse: Colorado's own insurance law requires that ABA providers treating children on commercial insurance hold recognized credentials, such as Registered Behavior Technician status -- but the state's Medicaid program imposes no such requirement on the behavior technicians who treat Medicaid-enrolled children. made five recommendations to Colorado, including the $42.6 million refund; Colorado disagreed with the refund, agreed with three recommendations, and partially agreed with one. Maine received four recommendations, including its $28.7 million refund; Maine "potentially concurred" with the refund and concurred with the rest.
The takeaway
- The spending outran the paperwork behind it. Colorado's ABA Medicaid payments nearly quadrupled from 2019 to 2024, and when finally checked a sample of that spending, all 100 sampled months had a compliance problem.
- This is not a one-state story -- it's an emerging pattern. Four states audited in the same series have now produced a combined $197.9 million in estimated improper ABA/RCS payments, with Colorado and Maine both showing 100-of-100 sampled months flagged.
- A state can require a credential for privately insured children and skip it for Medicaid ones. Colorado's own law requires ABA credentialing for commercially insured children; its Medicaid program does not require the same of providers treating children on Medicaid.
Figures are from Reports A-09-24-02004 (Colorado, Feb. 2026) and A-01-24-00006 (Maine, Jan. 2026), both read directly. Indiana and Wisconsin figures are drawn from the Colorado report's own citation of those two earlier audits in the same series and were not independently re-verified against the underlying Indiana/Wisconsin reports. 'Potentially improper' payments are those could not fully verify against documentation -- they are estimates of exposure, not confirmed overpayments, and are reported separately from the confirmed-improper totals throughout this piece.
Sources(2) ▾
- U.S. Department of Health and Human Services Office of Inspector General, Colorado Made at Least $77.8 Million in Improper Fee-for-Service Medicaid Payments for Applied Behavior Analysis Provided to Children (A-09-24-02004) (2026-02-25) — Colorado's ABA spending growth (2019-2024), the 100-of-100 sampled enrollee-months with improper/potentially improper payments, the improper/potentially-improper category breakdowns, the $77.8M/$207.4M estimates, the credentialing gap, the five recommendations and Colorado's partial disagreement, and the report's own citation of the Indiana and Wisconsin audits in the same series oig.hhs.gov · original document
- U.S. Department of Health and Human Services Office of Inspector General, Maine Made at Least $45.6 Million in Improper Fee-for-Service Medicaid Payments for Rehabilitative and Community Support Services Provided to Children Diagnosed With Autism (A-01-24-00006) (2026-01-16) — Maine's RCS spending growth (2019-2023), the 100-of-100 sampled enrollee-months finding, the improper/potentially-improper category breakdowns, the $45.6M/$22.4M estimates, and the four recommendations oig.hhs.gov · original document
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Applied Behavior Analysis (ABA) is a therapy for managing autism symptoms. In at least one state, Medicaid billing for it has grown sharply: Colorado's fee-for-service ABA payments rose from $60.1 million in 2019 to $230.3 million in 2024. 's inspector general is now several audits into a series examining whether states' ABA billing complies with federal rules. In Colorado and Maine, the two audits available in full, the finding was total: all 100 sampled enrollee-months in each state included a payment that was improper or potentially improper. Combined with two earlier audits in the same series, has now documented an estimated $197.9 million in improper ABA-related Medicaid payments across four states.