The Question · ABA · Compliance
Four OIG audits. Every sample had an error. Is your ABA file next?
HHS-OIG has now published four state audits of Medicaid ABA payments. In each one, all 100 sampled enrollee-months had at least one improper or potentially improper claim line. Most findings were documentation, not care that never happened. Here is what auditors flagged, where a documentation defect turns into a bigger problem, and how to check your own files.
By ASP-RCM Editorial, Healthcare RCM Practice · Updated
The question we asked on LinkedIn
When OIG finds a documentation defect in 100 of 100 samples, at what point does it stop being paperwork and become a false claim?
Improper payments, 4 states
At least this much, in fee-for-service ABA, per OIG
Of samples had an error
100 of 100 sampled enrollee-months, in all 4 audits
Audits in progress
8 projects in the OIG series, finish estimated FY2027
Growth in Medicaid ABA spend
$1.94B in 2021 to $10.1B in 2025, per CMS
Improper payments found, by state
Minimum improper amounts from each OIG report. Potentially improper amounts come on top of these.
Source: HHS-OIG reports A-09-24-02004, A-09-22-02002, A-01-24-00006 and A-06-23-01002.
The four reports at a glance
| State | Report issued | Improper (at least) | Federal share to refund | Report |
|---|---|---|---|---|
| Indiana | Dec 16, 2024 | $56.0M | $39.4M | A-09-22-02002 |
| Wisconsin | Jul 10, 2025 | $18.5M | $12.3M | A-06-23-01002 |
| Maine | Jan 16, 2026 | $45.6M | $28.8M | A-01-24-00006 |
| Colorado | Feb 25, 2026 | $77.8M | $42.6M | A-09-24-02004 |
The state agency refunds the federal share, then recovers from providers. OIG also asked each state to review a further set of potentially improper payments.
What the auditors kept finding
Pulled from the findings and recommendations in the four reports.
Assessments missing or unsigned
Services delivered with no required assessment, or assessments without staff or parent signatures (Maine).
Thin session notes
Notes that did not describe the service, the goals addressed or the data collected, so billed time was unsupported.
97155 and 97156 not supported
Protocol modification and family guidance billed without the documentation each code needs (Indiana, Wisconsin, Colorado).
Wrong rendering level on 97153
Wisconsin was told to pay 97153 based on the specialty of the person who actually delivered it.
Credentialing gaps
Colorado was told to guide providers on ABA credentialing requirements.
Diagnosis and referral rules
Indiana and Colorado were told to check that diagnostic evaluations and referrals met state rules before ABA was authorized.
The red flags CMS gave every state in August 2026
The CMS ABA toolkit lists these as signs of possible improper billing. State auditors and managed care plans will use them.
Identical documentation
The same wording across children, by provider or clinic.
Hours with no progress
Excessive hours, especially when they continue without better outcomes.
Group over 10%
Group therapy making up more than 10 percent of treatment time.
Two staff, one child
High staffing ratios with no clinical reason.
Overlapping treatments
Services that overlap in time or purpose.
No caregiver engagement
Plans with no real parent or caregiver participation.
When a documentation defect becomes a bigger problem
A general map, not legal advice. Talk to healthcare counsel the day you find a pattern.
You find a defect
An internal review finds notes or signatures that do not support billed units.
Measure it
Sample, quantify and decide if it is a one-off or a pattern. Do it promptly and in good faith.
Return what is owed
Federal law requires an identified overpayment to be reported and returned within 60 days. Medicaid money goes back to the state.
Fix the cause
A corrective action plan with training and re-audit fits documentation errors.
Escalate if it looks knowing
Evidence of knowing or reckless billing is where counsel weighs a self-disclosure.
Corrective action plan or self-disclosure?
The False Claims Act reaches claims made knowingly, which includes deliberate ignorance and reckless disregard.
Signs it may be more than paperwork
- The same defect across many children and months
- Staff raised it before and nothing changed
- Units billed that no note supports at all
- Billing by someone without the required credential
Signs a corrective action plan fits
- Isolated errors with services clearly delivered
- Found by your own review and fixed fast
- Overpayments quantified and returned
- Training and re-audit show the fix held
Audit-ready check for one child's file
Pick a child at random and check the last authorization period.
Most OIG findings were about paper, not care. That is good news only if you find it first: sample your own claims each quarter the way an auditor would, and return what you cannot support.
Questions operators ask next
What did the OIG ABA audits find?
HHS-OIG audited fee-for-service Medicaid ABA in Indiana, Wisconsin, Maine and Colorado. In each, all 100 sampled enrollee-months had at least one improper or potentially improper claim line, adding up to at least $197.9 million in improper payments. Common findings were missing or unsigned assessments, session notes that did not support billed time, and unsupported 97155 and 97156 services.
Which states are next for an OIG ABA audit?
OIG lists eight projects in the series. Four are published and four are in progress, with completion estimated in fiscal year 2027. OIG does not publish the remaining states until each report is out, so every state Medicaid ABA program should prepare as if it is next.
How long do I have to return an ABA overpayment?
Federal law requires an identified overpayment to be reported and returned within 60 days. For Medicare, CMS has allowed up to 180 days of timely, good-faith investigation before the clock starts since January 2025. Medicaid overpayments go back to the state program, and states add their own rules. Confirm the steps with counsel.
Is a documentation error a false claim?
Not by itself. The False Claims Act covers claims made knowingly, which includes reckless disregard. Isolated errors that are found, fixed and repaid usually fit a corrective action plan. A pattern that continues after people knew about it is where legal risk rises and counsel should be involved.
Find the gaps before an auditor does
We sample your own ABA claims the way an auditor would: assessment, plan, authorization, session note and units, line by line. A senior ABA partner walks you through the findings in a free 30-minute call.
Keep reading
Sources
- HHS-OIG, Audits of Medicaid ABA for Children Diagnosed With Autism (series SRS-A-25-029)
- HHS-OIG, Colorado report A-09-24-02004, February 2026
- HHS-OIG, Maine audit news release, January 22, 2026
- HHS-OIG, Indiana report A-09-22-02002, December 2024
- HHS-OIG, Wisconsin report A-06-23-01002, 2025
- CMS, Medicaid and CHIP Applied Behavior Analysis Toolkit, August 2026
Checked November 4, 2026. General information on billing operations, not legal advice. If you find a pattern of unsupported billing, speak to healthcare counsel before acting.