Characteristics of National Disability Insurance Scheme (NDIS) participants, 2019: Analysis of linked data

ABS recently linked National Disability Insurance Scheme (NDIS) data to the Multi-Agency Data Integration Project (MADIP). The MADIP is a secure data asset combining information on health, education, government payments, income and taxation, employment, and population demographics (including the Census) over time. NDIS data in scope of this linkage included data for all active Scheme participants as at 31 December 2019. The aim of this linkage was to test the feasibility of including NDIS data in the enduring MADIP and to showcase the utility of linked NDIS data. This analysis presents insights about the service use and sociodemographic characteristics of NDIS participants in scope using a selection of key MADIP datasets. For more information on the scope and technical details of the linkage, see the Technical Note.

Key definitions

MADIP Person Linkage Spine

A key piece of linking infrastructure that serves as a base dataset representing the Australian population between 2006 and 2020. Connected to the Spine are several analytical datasets providing information about various aspects of the lives of Australians, some of which have been used in the following analysis.

NDIS participants

Refers to active NDIS participants as at 31 December 2019 who linked to the MADIP spine (for more information on linkage rates, see the Technical Note).

Rest of population

Refers to the estimated Australian population based on 2016 Census data (where the Census record linked to the MADIP spine) excluding NDIS participants (as defined above). Note this population includes people with disability who were not NDIS participants, as well as people without disability.

Age

Age variables have been selected to reflect a person's age during the analytical dataset reference period and therefore differ depending on the analytical dataset.

For more information on the analytical datasets, age and other factors to consider when interpreting results, see the relevant notes at the beginning of each section, along with more detailed information in the Technical Note.

The NDIS largely provides support to people aged under 65 years(1) with permanent and significant disability. 

In comparing NDIS participants to the ‘rest of population’, it is important to note the differing age distributions, especially given the correlation between age and many factors such as health service use and housing circumstances that have been analysed in this publication.

Of the 337,300 NDIS participants as of 31 December 2019 (who linked to the MADIP spine), almost two-thirds (65.5%) were aged under 35 years, compared to 41.0% of the rest of population.

Almost two-thirds (62.0%) of the 337,300 NDIS participants were male, largely due to the significant number of people among the NDIS population with autism, and the higher prevalence of autism among males(2). In comparison, among the rest of population there were a fairly even number of males and females (48.9% of the rest of population were male).

When comparing results within the NDIS population, it is important to understand the population’s profile across primary disability type. While NDIS participants may have one or more disabilities for which they need assistance, their primary disability is the disability that impacts most on a person’s daily life(3).

The most common primary disability types among NDIS participants (in scope of this analysis) were:

• autism (30.9% of all participants)
• intellectual disability (20.2%)
• psychosocial disability (9.1%)

The age profiles differ considerably across primary disability types, with some disability types made up entirely of younger people. This is important to keep in mind when interpreting results.

The MADIP is a secure data asset combining information on health, education, government payments, income and taxation, employment, and population demographics (including Census) over time.

Analysis in this publication uses linked NDIS data, in conjunction with the following four MADIP datasets to provide a range of high-level insights about NDIS participants’ use of health services and medications, support needs, housing circumstances and sociodemographic characteristics:

• 2019-20 Medicare Benefits Schedule (MBS)
• 2019-20 Pharmaceutical Benefits Scheme (PBS)
• 2016 Census of Population and Housing (Census)
• 2020 Social Security Related Information (SSRI)

Some comparative analysis for the ‘rest of population’ is also included.

The potential of linked NDIS-MADIP data is far broader than what is included in the following high-level analysis. Interested researchers should visit the ABS website for further details around applying for access to linked NDIS-MADIP data.

The rest of population has a much older profile than the NDIS population (that is, there are proportionally more people over the age of 65 in the rest of population compared with a younger NDIS population). Given the differing age profiles and the correlation between service use and age, some MBS analysis has been presented for the 0 to 64-year cohort, in addition to analysis for all ages. The intention is for these comparisons to aid interpretation in the way the differing age profiles may influence results.

In 2019-20, of the 337,300 linked NDIS participants of all ages, nearly all (95.6%) accessed an MBS service at least once, compared with 87.1% of the rest of population (when limited to those aged 0 to 64 years, 95.5% of NDIS participants and 86.8% of the rest of population).

The services most likely to be accessed (at least once) by NDIS participants in 2019-20 were:

• General Practitioner (GP) services (91.1%)
• Pathology tests (53.3%)
• Pathology collection (52.7%)
• Specialists (53.2%)

When compared to the rest of population, the most commonly accessed services were similar for the two populations. While overall a larger proportion of NDIS participants (of all ages) accessed GP services, specialists and GP enhanced primary care services, those in the rest of population were more likely to have used pathology tests and collection services, diagnostic imaging and optometry services.

Among NDIS participants (of all ages) who used at least one MBS service in 2019-20, the average number of visits to all MBS services (21.0 visits) was higher than the rest of the population (18.4 visits) (when limited to those aged 0 to 64 years, the average number of visits was 20.5 for NDIS participants and 14.5 for the rest of population).

This was consistent across all age groups. The difference was largest for:

• those aged 45-54 years where NDIS participants had almost twice the number of average visits to MBS services (33.6 visits) compared with the rest of population (16.9 visits)
• those aged 35-44 years (average of 29.5 visits for NDIS participants compared with 15.3 visits for the rest of population).

For both populations, the average number of visits to MBS services generally increased with age.

The two most commonly accessed MBS services (GP attendances and pathology tests) were also the most frequently used services. Among NDIS participants (of all ages) in 2019-20:

• there were almost 2.5 million GP attendances, averaging 8.0 visits per NDIS participant who accessed this service (compared with an average of 6.5 visits for those who used this service in the rest of population)
• there were almost 1.4 million pathology tests, averaging 7.6 tests per NDIS participant who accessed this service (compared with an average of 6.7 tests for those who used this service in the rest of population).

There was little variation across disability type in terms of overall use of MBS services, with more than 90% of all NDIS participants accessing at least one service in 2019-20, regardless of their primary disability. However, people with some primary disability types were more likely to access specific services compared with others.

Among NDIS participants (of all ages) in 2019-20:

• those with multiple sclerosis were most likely (of any primary disability type) to have seen a specialist (78.7%), while those with a hearing impairment were least likely to have visited a specialist (42.5%)
• those with psychosocial disability or stroke were most likely to have accessed GP enhanced primary care (63.2% and 62.5% respectively).

People with psychosocial disability accessed the highest average number of MBS services in 2019-20 (an average of 40.5 visits per person), followed by those with multiple sclerosis (an average of 38.1 visits per person). It is important to take into consideration the different age profiles of primary disability groups when interpreting results (see Comparisons within the NDIS population section).

MBS service use generally increased with age among both NDIS participants and the rest of population. However, use of specialists among NDIS participants showed a different pattern.

Specialists

NDIS participants (of all ages) were 1.7 times more likely to attend a specialist at least once (53.2%) than the rest of population (31.7%) (when limited to those aged 0 to 64 years a larger difference was observed, 53.0% of NDIS participants compared with 26.1% of the rest of population). This was particularly the case among young children. In 2019-20:

• almost two-thirds (63.7%) of NDIS participants aged 0-6 years had seen a specialist at least once, almost 4 times the rate of the rest of population aged 0-6 years (16.7%)
• over half (58.6%) of NDIS participants aged 7-14 years had seen a specialist at least once, almost 4 times higher than the rest of population aged 7-14 years (15.6%).

Although a higher proportion of young NDIS participants accessed specialist services at least once (compared with the rest of population), the average number of visits to specialists generally increased with age, similar to other services. Of NDIS participants who accessed specialist services in 2019-20:

• children aged 7-14 years had the lowest average number of specialist visits (2.9 visits per person) followed by children aged 0-6 years (3.1 visits per person)
• those aged 55-64 years had an average of 5.2 specialist visits per person.

The rest of population has a much older profile than the NDIS population (that is, there are proportionally more people over the age of 65 in the rest of population compared with a younger NDIS population). Given the differing age profiles and the correlation between medicine use and age, some PBS analysis has been presented for the 0 to 64-year cohort, in addition to analysis for all ages. The intention is for these comparisons to aid interpretation in the way the differing age profiles may influence results.

In 2019-20, of the 337,300 NDIS participants (of all ages) 79.7% accessed at least one PBS subsidised medicine, compared with 66.3% of the rest of population (when limited to those aged 0 to 64 years, 79.2% of NDIS participants and 61.7% of the rest of population).

Overall NDIS participants (of all ages) accessed a total of 5.1 million subsidised medicines. Among NDIS participants who accessed at least one PBS medicine in 2019-20, the average number of scripts was 18.9, compared with 14.5 for those in the rest of population (when limited to those aged 0 to 64 years, the average number of scripts was 18.5 for NDIS participants and 9.9 for the rest of population).

In 2019-20, among NDIS participants:

• the use of PBS medicines was higher than the rest of population across all age groups
• the greatest difference was among those aged 7-14 years (70.2% of NDIS participants accessed PBS medicines, compared with 42.1% for the rest of population).

The difference between the two populations in the proportion of people who accessed PBS medicines generally diminished with increasing age.

When compared to the rest of population, not only did a greater proportion of NDIS participants access PBS medicines, they also accessed a higher average number of scripts across all age groups. NDIS participants in the age groups from 7 to 44 years had an average number of scripts almost three times higher than those of the same age in the rest of population.

There was some variation in the types of medicines accessed by NDIS participants compared to the rest of population. In 2019-20, of the 337,300 NDIS participants (of all ages), the most common types of PBS medicines by body system accessed (at least once) were:

• Anti-infectives for systemic use e.g. antibiotics (44.4% compared with 37.0% of the rest of population)
• Other nervous system medicines e.g. to help quit smoking, and to assist with other nervous system conditions (27.2% compared with 16.5% of the rest of population)
• Nervous system antidepressants used to alleviate depression (26.4% compared with 13.4% of the rest of population)
• PBS medicines for the cardiovascular system were accessed by around one-quarter of both NDIS participants (25.0%) and the rest of population (24.5%).

For more information about the PBS body system classification of medicines see the Technical Note.

Among NDIS participants (of all ages), people with the following primary disability types were most likely to have accessed at least one PBS medicine in 2019-20:

• Multiple sclerosis (97.5% of whom accessed at least one PBS medicine in 2019-20)
• Stroke (96.1%)
• Psychosocial disability (95.7%)
• Spinal cord injury (95.5%)

Of those who accessed at least one PBS medicine, those with the following primary disability types had the highest average number of scripts in 2019-20:

• Stroke (33.6 prescriptions)
• Psychosocial disability (30.7)
• Multiple sclerosis (28.4)

It is important to take into consideration the different age profiles of primary disability groups when interpreting results (see Comparisons within the NDIS population section).

Disability is generally associated with lower rates of employment and labour force participation(5). Among the 153,600 NDIS participants within the scope of this analysis (living in households/private dwellings) aged 15-64 years:

• 27.3% were in the labour force, less than half the rate of the rest of population (76.9%)
• 23.4% were employed, less than one third the rate of the rest of population (71.7%)
• 4.0% were unemployed, compared to 5.3% of the rest of population.

Of NDIS participants within the scope of this analysis (living in all dwelling types aged 15 years and over), around one in six (15.8%) had volunteered for an organisation or group in the previous 12 months, compared with one in five people (20.3%) of the same age in the rest of population.

Rates of volunteering among NDIS participants varied according to primary disability type:

• one-quarter (24.4%) of those with visual impairment had volunteered
• around one in five (21.0%) of those with hearing impairment had volunteered.

NDIS participants generally lived in households with a lower level of equivalised household income.

Among NDIS participants within the scope of this analysis (people of all ages living in households/private dwellings):

• over half (56.6%) lived in households with an equivalised income under $800 per week, compared with 38.4% of the rest of population
• 9.2% lived in households with an equivalised income of over $1,500 per week, less than half that of the rest of population (20.5%).

Results showed some variation in household income across age. The likelihood of living in a household with a low (reported) equivalised weekly income:

• increased with age for NDIS participants (up to 35 years and then remained relatively stable)
• decreased with age for the rest of population (up to 54 years).

The disparity between the two populations increased across age (up to 54 years).

Given the range of impacts that different disabilities can have on an individual or carer’s ability to work, certain disabilities were associated with lower household incomes. Of NDIS participants within the scope of this analysis (people of all ages living in households/private dwellings), those with the following primary disability types were more likely than those with other primary disability types to be living in households with an equivalised weekly income under $800:

• Psychosocial disability (73.4%)
• Acquired brain injury (63.8%)
• Intellectual disability (61%).

Of NDIS participants within the scope of this analysis (people of all ages living in all dwelling types) most (94.6%) lived in a private dwelling, with around one in twenty (5.3%) living in non-private dwellings(6) (compared with around 2.6% of the rest of population).

The likelihood of living in a non-private dwelling increased for certain disability types. Of NDIS participants within the scope of this analysis:

• almost one in seven with psychosocial disability (15.2%) or acquired brain injury (14.7%) lived in non-private dwellings
• around one in 8 (12.2%) with disability associated with stroke lived in non-private dwellings.

It is important to take into consideration the different age profiles of primary disability groups when interpreting these results (see Comparisons within the NDIS population section).

Linked NDIS-MADIP data showed that NDIS participants were more likely to be living in rental accommodation than the rest of population.

Of NDIS participants within the scope of this analysis (people of all ages living in households/private dwellings):

• 39.7% were living in a rented home, compared with 28.7% of the rest of population
• 36.6% were living in a home owned with a mortgage, compared with 41.1% of the rest of population
• around one in five (19.6%) lived in a home that was owned outright, compared with 26.5% of the rest of population.

In general, the likelihood of living in rental accommodation was higher among those with a low household income and this was particularly pronounced among NDIS participants. Among NDIS participants within the scope of this analysis (people of all ages living in households/private dwellings):

• almost two-thirds (62.0%) of those in a household with an equivalised weekly income below $400 per week were renting, compared to 45.9% of the rest of population living in a household with an equivalised weekly income below $400 per week
• almost half (45.8%) of those in a household with an equivalised weekly income between $400-$799 per week were renting, compared to 32.7% of the rest of population with that income.

Tenure type also varied across age, in particular the likelihood of living in rental accommodation.

NDIS participants within the scope of this analysis (people of all ages living in households/private dwellings):

• were more likely to be living in rental accommodation than the rest of population among all age groups (except those aged 15-34 years)
• those aged 35-44 years were most likely to be living in rental accommodation (45.0%) followed by those aged 45-54 years (44.1%, almost twice as high as the rest of population for this age group, 22.7%).

The disparity between the two populations in the rate of those living in rental accommodation generally increased with age.

Housing suitability(7) is an indicator of whether a private household is living in suitable accommodation for the number of people living there. A home with spare bedrooms suggests the occupants live in relative comfort.

Of NDIS participants within the scope of this analysis (people of all ages living in households/private dwellings):

• 59.1% were living in a home with spare bedrooms, compared with 66.7% of the rest of population
• just 7.7% were living in a home where extra bedrooms were needed, compared to 6.7% of the rest of population.

People with disability may be eligible for financial support, with varying eligibility requirements for different social support payments. The Disability Support Pension (DSP)(8) is a payment for people with permanent physical, intellectual or psychological disability that stops them working and is limited to people aged 16 years and over. Children under 16 with disability may be eligible for other financial supports paid to their parents/carers.

The following analysis is limited to NDIS participants who were in the Scheme at 31 December 2019 (and who linked to the MADIP spine) and does not include information about social support payments received by parents/carers of people with disability. Therefore, it is likely this analysis does not represent the full picture of income supports provided to NDIS participants, particularly for children under 16 years and for the primary disability groups predominantly made-up of younger people.

Among NDIS participants of all ages who were in the Scheme at 31 December 2019 (and who linked to the MADIP spine), half (50.3%) received some form of social support payment in 2020, comprising:

• Disability Support Pension (45.3%) - these people may or may not have also received other support payments
• Other support payment (5.0%)

Given DSP eligibility, the proportion of NDIS participants who received DSP increased to 75.5% when limiting to those aged 16 years and over.

Across primary disability types, the proportion who received a social security payment varied. Of NDIS participants (of all ages) who were in the Scheme at 31 December (and who linked to the MADIP spine), those most likely to be receiving a social security related support payment were:

• people with psychosocial disabilities (94.6%)
• people with acquired brain injury (80.6%)
• people with disabilities associated with stroke (80.9%)

Technical note describes the data sources, scope, preparation, and method used to link 2019 National Disability Insurance Scheme (NDIS) administrative data to the Multi-Agency Integration Project (MADIP).

NDIS data was linked to the MADIP spine and then analysed, in conjunction with other MADIP datasets, to provide insights into the sociodemographic characteristics, and use of health services, medicines and receipt of social security payments by NDIS participants.

The following technical information is relevant only to the results published in Characteristics of NDIS participants – analysis of linked data, 2019, and may not necessarily be relevant for other linkages involving NDIS data.

The data for this publication were produced using the following data sources:

National Disability Insurance Scheme (NDIS) administrative data

Administrative data for active participants in the NDIS as at 31 December 2019, including demographic and NDIS plan characteristics. The National Disability Insurance Agency collect information about participants in order to administer the Scheme and disseminate statistics for research and evaluation(9). Data for this linkage was provided by the NDIA to the ABS under a Public Interest Certificate.

MADIP person linkage spine

Linking infrastructure that serves as a base dataset representing the population ever resident in Australia between 2006 and 2020.

2016 ABS Census of Population and Housing

The 2016 Census measured the number and key characteristics of people who were in Australia on Census night, 9 August 2016.

Medicare Benefits Schedule administrative data

Medicare Benefits Schedule (MBS) administrative data for the 2019-20 financial year.

Department of Human Services collects data on the activity of all persons making claims through the MBS and provides this information to the Department of Health. Information collected includes the type of service provided (MBS item number) and the benefit paid by Medicare for the service. The item numbers and benefits paid by Medicare are based on the MBS which is a listing of the Medicare services subsidised by the Australian Government. Analysis in this publication includes MBS subsidised services, grouped by Broad Type of Service (see Appendix).

Pharmaceutical Benefits Scheme administrative data

Pharmaceutical Benefits Scheme (PBS) data for the 2019-20 financial year.

Department of Human Services provides data on prescriptions funded through the PBS to the Department of Health. The PBS lists all medicines available to be dispensed to patients at a Government-subsidised price. Analysis in this publication includes PBS subsidised mental health-related medications, grouped by PBS Body System (see Appendix).

Social Security and Related Information administrative data

Social Security and Related Information administrative data for the 2020 calendar year.

Australia collects information on the benefits claimed through Centrelink and provides this to the Department of Social Services for administration, research and evaluation purposes. Information collected includes type and amount of benefit(s) received.

The scope of the data is restricted to:

‘NDIS population’: active NDIS participants as at 31 December 2019 where the NDIS record linked to the MADIP spine.

‘Rest of population’: people who responded to the 2016 Census of Population and Housing where the Census record linked to the MADIP spine.

The following exclusions apply where additional administrative data is used:

Medicare Benefits Schedule

• Services that qualify for a benefit under the Department of Veterans' Affairs National Treatment Account.
• Persons who accessed services only through programs that do not use the Medicare processing system, for example, Aboriginal and Torres Strait Islander Health Programs.

Pharmaceutical Benefits Scheme

• The Repatriation Pharmaceutical Benefits Scheme, subsidised by the Department of Veterans’ Affairs.
• Persons who were supplied medications through programs not subsidised by the PBS;
• Persons accessing private prescription drugs, over the counter drugs, and drugs that cost less than the co-payment.

Social Security and Related Information

• Persons who were indirect beneficiaries, i.e. if a parent received a benefit on behalf of their child, the parent will be included in the dataset while the child will not.

The NDIS variables used for linking were name, geographies, date of birth and sex or gender.

Name

NDIS names were cleaned, standardised and anonymised.

Names were cleaned by removing nonsense values, removing special characters and titles. The cleaned names were then standardised by converting common nicknames, abbreviations, misspellings or variations on a first name to their 'origin name'. Any first name that could not be standardised was retained in its original form. Names were then anonymised.

Geography

The ABS Address Register provides a comprehensive list of all physical addresses in Australia and includes an Address Register ID (ARID) for each physical address. An anonymised version of ARID is used in data linkage projects. Addresses were geocoded to ARID, Mesh block, SA1, SA2, and SA4, according to the ASGS 2016 classification(10).

Date of Birth

Full date of birth, as well as day and year of birth were used in the NDIS linkage.

Deterministic Example

NDIS linkage was completed using deterministic linking. Deterministic linkage involves locating record pairs across the two datasets that match exactly or closely (according to pre-defined rules) on common variables. The deterministic linkage employed was designed using a three-stage approach. The matching rules and criteria were gradually broadened with each stage to tolerate greater differences in a field or expanding the geographic area in which a match can occur.

NDIS Linkage Results

A total of 337,347 links were achieved in the NDIS to MADIP spine linkage, resulting in a total NDIS linkage rate of 99.52%.

Linkage rates by sex, age and state are presented in Table 1. Very High linkage rates were achieved across all demographics, with slightly lower rates for persons living in the Northern Territory.

MADIP linkage spine and datasets

Information about the MADIP linkage spine and MADIP datasets can be found on the ABS Multi-Agency Data Integration Project (MADIP) website.

Table 2 shows the number of NDIS records (of the 337,347 which linked to the MADIP spine) where a corresponding record in the specified analytical dataset was available.

There are two reasons why NDIS records may not have a corresponding record in an analytical dataset:

• They did not have a record in the relevant dataset (e.g. Medicare Benefits Schedule – they did not use any MBS subsidised services in the specified reference period); or
• Their record in that specific dataset (e.g. MBS) did not link to the MADIP spine.