What Does 'Reasonable and Necessary' Actually Mean Under the NDIS?

You'll hear the phrase "reasonable and necessary" throughout the NDIS — it's the test used to decide whether a particular support will be funded in a participant's plan.

Broadly, a support needs to relate to the participant's disability, represent value for money, be likely to be effective, and take into account informal supports already in place, such as family assistance.

It also needs to be something the NDIS is responsible for funding, rather than a service that should be provided by another system, such as health or education, under a mainstream service agreement.

This is often where good evidence makes the biggest difference — a clear explanation from a treating professional of why a support is needed and how it connects to the participant's goals strengthens a funding request considerably.

If a request for a support is knocked back, participants have the right to ask for a review of that decision, and many successful reviews come down to providing clearer supporting evidence the second time around.