Claims spreadsheets and AI data leakage: what an NDIS invoice sheet gives away in ChatGPT or Claude.

Every NDIS service keeps a spreadsheet that turns shifts into claims. Staff paste it into ChatGPT or Claude, or upload the file, to find the rows that were rejected, check a formula or draft the email to a plan manager. The sheet is a table of identifiers: each participant, the NDIS number the NDIA uses to match claims, the support delivered, the hours and a status column that reveals which shifts are being questioned and why. This page marks every item in a month’s claims sheet that the Practice Standards and the Privacy Act bear on, and shows what travels with the file, then how the same checks run on Ermos inside the service.

The claims and invoice spreadsheet

Maintained by the service administrator through the month and used to submit claims. NDIA guidance on invoicing and record keeping expects providers to keep records of the supports they deliver, such as case notes, rosters and service agreements, to support the claims they make.

An invented claims sheet. The NDIS numbers are placeholders, and the rates are invented and are not NDIS price limits. Hover or tap any highlighted item for the analysis; the full list is below.

What leaves the service

1. 1
   Participant names

   Every participant in the month, one row per shift. Personal information the Information Management standard expects to be kept confidential, repeated down a column. Privacy Act guide.

2. 2
   NDIS numbers

   The number the NDIA uses to match a payment request to a participant’s plan. A column of them beside names makes impersonation and claims fraud easier. Treat it like a column of bank account numbers. Privacy Act guide.

3. 3
   The support each person receives

   Self-care, community access, daily living. A summary of what each person needs help with, which is health information about people with disability. Patient data guide.

4. 4
   A hold that reveals an incident

   A status that says a named man’s shift is under incident review. It tells a reader that something happened; the Incident Management Rules require the record of a reportable incident to be kept for 7 years.

5. 5
   A dispute and a missing note

   That a mother is disputing a charge through a complaint, and that a shift has no note behind it. Both are about the service’s own records. The note is what backs the claim, and complaint information is to be kept confidential and disclosed only if required by law or otherwise appropriate. Privacy Act guide.

6. 6
   Hours, rates and totals

   What the service charges and what each participant uses. Financial information about the participants’ plans and commercial information about the service. The rates in this sheet are invented.

7. 7
   A formula that reads another column

   A sum that totals paid claims. It has no personal data in it, though in a real workbook a formula can pull values from other sheets and files that travel with the upload.

8. 8
   The other tabs

   This workbook has tabs for plan managers, rates and notes. When a spreadsheet file is uploaded, everything in it goes: other sheets, hidden columns, cell comments, formulas that point at other files and properties such as the author.

What happens in Frontier Models (ChatGPT, Claude)

• The whole document is transmitted to the provider’s servers. On personal plans the user cannot choose where it is stored or processed, and for the major providers that has generally meant outside Australia, under that country’s legal process. Some business plans offer storage in Australia, but the provider still receives the content.
• On consumer tiers, prompts can be retained and used to train future models.
• The provider’s staff and systems can reach the content under the provider’s own policies.
• Once sent, the service no longer controls it. Retention and deletion happen on the provider’s terms.

The same document on Ermos

Part of AI data leakage in NDIS services.

Common questions