20% of children have developmental delay. What does this mean for them, their families and the NDIS?

Professor Bruce Bonyhady is often described as the architect of the National Disability Insurance Scheme (NDIS) and is co-chair of the panel reviewing it. He spoke last week about the sustainability challenges faced by the scheme.

Among the key issues identified was that 20% of Australian children experience learning difficulties, developmental concerns, developmental delay or are found to have disability. Bonyhady said this made it a “mainstream issue”. He added the NDIS was never designed to be the main support system for the majority of these children.

With the NDIS review due to report to state and federal ministers in October, the comments signal a re-calibration of the scheme.

This presents another challenge: which government systems outside the NDIS will embrace the large number of children who need developmental support?

What is a developmental delay?

Developmental delay is a general term that refers to young children who are slower to develop communication, physical, social, emotional and cognitive skills than typically expected. The pace of a child’s development can be measured in many ways, one of which is comparing their development to established milestones, such as when they learn their first word or when they learn to walk.

Many things can cause developmental delay. These include biological differences (such as genetic conditions), environmental challenges (including deprivation) or a combination of both. In many cases, the causes of a child’s developmental delay remain unknown.

Developmental delay is a term commonly used in clinical practice, but not included in official diagnostic manuals like the Diagnostic and Statistical Manual. This is because developmental delay is viewed as a temporary state in child development. It is most often used for children under five.

As children grow older, some developmentally catch up with their peers. Others continue to lag behind. At a certain point in development – typically around five - children in the latter group will start to be referred to as having a developmental disability.

Developmental disabilities are included in official diagnostic manuals and include autism, attention deficit hyperactivity disorder (ADHD), intellectual disability, specific learning disorders, communication disorders and developmental coordination disorder.

Read more: New national autism guideline will finally give families a roadmap for therapy decisions

Developmental delay and the NDIS

The NDIS has a specific definition of developmental delay which encompasses three areas. Children are considered to have a developmental delay if their delay is:

• due to mental or physical impairments
• substantially reduces functional capacity
• requires specialist services.

Around 11% of all NDIS participants are classified as having a developmental delay. There are also a significant number of children with developmental delay who are not within the NDIS. Taken together, these groups make up about 20% of Australian children under five.

While there is a general community view that developmental delay is an increasing issue in Australia, there is a lack of data tracking over time to understand if this view is accurate.

Our clearest indication comes from Australian Early Development Census, which surveys more than 300,0000 children entering primary school.

The latest available data indicate there are now slightly fewer children who are “developmentally on track” (down from 55.4% in 2018 to 54.8% in 2021) and an increase in the number of children who are “developmentally vulnerable” in any one area of development (up from 21.7% in 2018 to 22% in 2021).

Read more: A decade on, the NDIS has had triumphs, challenges and controversies. Where to from here?

Supporting children with developmental delay

There has always been a large number of children experiencing developmental delay. But the fragmentation across state/territory and Commonwealth health and disability systems has meant the true scale of children struggling with development has not been clear. The unified system of the NDIS has made the percentage of children with delays clearer.

But, as Bonyhady notes, the NDIS was not designed to support all these children. The NDIS was meant to complement existing systems such as health and education, and to provide additional support to children with the most significant disability impacts. This figure is estimated to be a small proportion of the 20% of children who meet criteria for developmental delay.