• States and territories and the Australian Government Department of Social Services (DSS) (‘the jurisdictions’) collect data on the disability support services provided under the National Disability Agreement (NDA).
• The AIHW compiles the annual Disability Services National Minimum Data Set (DS NMDS) from the information supplied by the jurisdictions.
• Services provided under the NDA vary by jurisdiction and year.
• The counts of service users depend on the accuracy of the statistical linkage key. This varies by jurisdiction and year.
• While every effort is made to incorporate responses from all service type outlets provided under the NDA, each year a small number are not included. This varies by jurisdiction and year.
• Some outlets do not report on all service users, due to administration or other errors, and it is not possible to accurately estimate the number of service users who may be missing from the data as a result. This varies by jurisdiction and year.
• Non-response rates to data items vary by jurisdiction and year.

The Australian Institute of Health and Welfare (AIHW) is a major national agency set up by the Australian Government under the Australian Institute of Health and Welfare Act 1987 to provide reliable, regular and relevant information and statistics on Australia's health and welfare. It is an independent Commonwealth entity established in 1987, governed by a management Board, and accountable to the Australian Parliament through the Health Portfolio.

The AIHW aims to improve the health and wellbeing of Australians through better health and welfare information and statistics. It collects and reports information on a wide range of topics and issues, ranging from health and welfare expenditure, hospitals, disease and injury, and mental health, to ageing, homelessness, disability and child protection.

The Institute also plays a role in developing and maintaining national metadata standards. This work contributes to improving the quality and consistency of national health and welfare statistics. The Institute works closely with governments and non-government organisations to achieve greater adherence to these standards in administrative data collections to promote national consistency and comparability of data and reporting.

One of the main functions of the AIHW is to work with the states and territories to improve the quality of administrative data and, where possible, to compile national datasets based on data from each jurisdiction, to analyse these datasets and disseminate information and statistics.

The Australian Institute of Health and Welfare Act 1987, in conjunction with compliance to the Privacy Act 1988, ensures that the data collections managed by the AIHW are kept securely and under the strictest conditions with respect to privacy and confidentiality.

For further information see the AIHW website www.aihw.gov.au.

The AIHW has been maintaining a minimum data set on disability support services since 1994, firstly as a snapshot collection and then from 2003–04 as an annual collection. The AIHW receives, compiles, edits and verifies the DS NMDS data in collaboration with jurisdictions, which retain ownership of the jurisdictional level data and must approve any jurisdictional level output before it is released.

Data are released annually.

The DS NMDS cannot be compiled for a given year until each jurisdiction is able to supply and sign-off data for that year. Sign-off of jurisdictional data submissions is due by the December following the end of the collection period. Data are required to be released by the end of the following June. For the 2017–18 data, the final jurisdiction provided sign-off 30 November 2018.

The AIHW has been reporting on disability support services collected under the various iterations of the national disability agreements since 1994.

The AIHW website provides disability services reports and data which can be downloaded free of charge. Additional disaggregation of data may be requested via a customised data request. The length of time it takes to complete a request depends on several factors and a charge might apply to recover costs. General enquiries about AIHW publications can be made to the Digital and Media Communications Unit on (02) 6244 1032 or via email to [email protected].

The main counts of the DS NMDS collection are service users and service type outlets. A service type outlet is a statistical counting unit of an agency that provides a particular NDA service type at, or from, a discrete location. Data are collected, usually by agencies, for each service type outlet.

Data on service users are collected against the service types (service type outlets) over the collection period. Note that service user data are not collected in relation to two of the seven service groups—‘advocacy, information and alternative forms of communication’ and ‘other support’. Further, the level of information required to be collected varies according to the particular service type. For more information on what information is collected against each service type as well as a description of each service type, see the associated Disability Services NMDS 2017–18 METeOR entry or the DS NMDS data guide.

The scope of services included in the DS NMDS can vary in terms of the programs that are provided under the NDA across jurisdictions as well as in what programs are included in the data collection. See ‘Coherence’ for further details.

The National Disability Insurance Scheme (NDIS) was launched in trial sites from 1 July 2013, with progressive roll-out to full scheme from 1 July 2016. It is expected that many NDA service users will transition to the NDIS and hence exit from the DS NMDS collection over time. This affects data from 2013–14 onwards. Some service type outlets may also be less responsive because of the complexities associated with the changeover to the NDIS. See ‘Coherence’ for further details.

More information on the DS NMDS is available on the AIHW website. This includes the DS NMDS collection materials.

The DS NMDS collects data on disability support services provided under the NDA. States and territories and the Australian Government collect data from agencies providing these services and supply it to the AIHW. These are compiled into the DS NMDS and released annually.

Some service type outlets have a large number of service users who have minimal contact, such as information and referral services. These service types are required to submit service type outlet information to the DS NMDS but are not required to submit service user or service received information.

See 'accuracy' for further information on coverage.

The DS NMDS is highly relevant for reporting on the use of disability support services under the NDA. The data are used for many purposes, including by policy-makers and researchers. The DS NMDS also contains a statistical linkage key for each service user. This enables researchers to link their database to the DS NMDS (noting that such data linkage can only be done after receiving approvals from various ethics committees).

Metadata information for the DS NMDS are published in METeOR (Disability Services NMDS 2017–18), and in the DS NMDS data guide.

Each year, when all the jurisdictions’ data are compiled into the DS NMDS, a national validation and data linkage process is undertaken.

To form service user counts, a statistical linkage key is used. The statistical linkage key enables the number of service users to be estimated from data collected from service type outlets and agencies. During any given financial year, a service user can receive services from:

• more than one service type outlet
• more than one agency
• multiple jurisdictions—across state/territory borders, and/or a combination of Australian Government and state/territory services.

In each of these cases, service user counts can be estimated by using the statistical linkage key. All counts of the number of service users depend on the accuracy of the statistical linkage key. A linkage key is considered to be invalid if any, or all, parts of the key are missing (excluding sex). To link records within the DS NMDS, the statistical linkage key components of each record for a service received are compared electronically with the statistical linkage key components of all other records. Records that have matching statistical linkage keys are assumed to belong to the same individual service user and are linked.

As with all collections that use a statistical linkage key to identify service users, a small degree of mis-identification is expected. That is, because the statistical linkage key is not a unique identifier, there is a small probability that some of the linked records do not belong to the same individual, and, conversely, that some records that did not link do belong to the same individual. Records with missing or invalid statistical linkage keys cannot be linked to other records, and so must be treated as belonging to separate individual service users. This might result in the number of service users being slightly overestimated. In 2017–18, 0.3% of records had an invalid statistical linkage key.

Service type outlet and service user participation rates, as well as the response rates to various data items, need to be considered when interpreting data. These vary across years and jurisdictions. Data can be considered more reliable as participation and response rates increase.

Jurisdictions report their service type outlet participation rates—the number of outlets that contributed to the DS NMDS collection compared with the total number of outlets in the jurisdiction. While every effort is made to incorporate responses from all service type outlets provided under the NDA, each year a small number are not included.

Likewise, it is recognised that some outlets do not report on all service users, due to administration or other errors, and it is not possible to accurately estimate the number of service users who might be missing from the data as a result. All service type outlets are required to estimate the number of service users they helped over the year; however, analysis of these estimates and comparison with jurisdictional reports indicate that such estimations can be of poor quality.

Non-response rates to data items can vary across jurisdictions and years. High levels of non-response reduce the validity and reliability of data, and items with high proportions should be considered with care, especially when comparing data across jurisdictions and collection years. These generally occur when a service user or service type outlet does not provide/collect information on a service user, or when information cannot be derived by statistical linkage processes. In some instances, particular service types are not required to submit data for all measures.

Tabular information on the response rates, participation rates, and the validity and completeness of the statistical linkage key are provided in the supplementary tables to the annual DS NMDS bulletins.

DS NMDS data are collated and published annually by the AIHW.

Service type outlet and service user participation rates, as well as the response rates to various data items, vary across years and jurisdictions (see ‘Accuracy’ for further detail).

The scope of services vary across jurisdictions and years in terms of the programs that are provided under the NDA and how they are classified. For example:

• In most jurisdictions, specific mental health services are provided under health, rather than disability, portfolios. However, in Victoria and Queensland, specialist psychiatric disability services are included under the NDA.
• Early intervention services for children with disability fall within the disability support system in some states but are administered under the education portfolio in others.
• From 2012–13, the Northern Territory DS NMDS data includes people using Basic Community Care services. Other jurisdictional data do not.
• Residential rehabilitation services within Victoria's psychiatric disability rehabilitation and support sector (PDRSS) are classified by Victoria as non-residential accommodation support services in the DS NMDS, rather than as residential accommodation support services.
• Both the NDIA and the Western Australian Government operated NDIS trials in Western Australia from 1 July 2014 to 30 June 2017. DS NMDS data includes the Western Australian Government-operated NDIS trial sites for those years as these were considered to be services provided under the NDA; whereas service users who moved to the NDIA-operated trial sites were considered to have transitioned to the NDIS from the date at which they had an approved NDIS plan.
  On 1 July 2017, the dual NDIS trial ceased and the Western Australian Government began administering the NDIS in Western Australia. For this reason, as at 30 June 2017, service users of the Western Australian Government-operated trial sites were considered to have transitioned to the NDIS. These service users are flagged in 2016–17 DS NMDS data as having transitioned to the NDIS and are excluded from the 2017–18 data.

While there have been some changes in the collection over the years, some meaningful comparisons can be made over time, particularly from 2007–08 onwards. Some major changes to the collection over time include:

• Changes in collection period/method—from 1994 to 2002, data were collected under the Commonwealth State Disability Agreement Minimum Data Set (CSDA MDS) which was run as a ‘snapshot’ collection. Data from the snapshot collections are not strictly comparable to that from the annual data collections (the CSTDA NMDS for 2003–04 to 2008–09 and the DS NMDS from 2009–10 onwards).
• Changes to service type codes—
  • from 1 October 2008, targeted support services (5.04) previously delivered by the Australian Government and included in the service group ‘employment services’ were transferred to state/territory governments and are now distributed across various state and territory service type codes
  • the use of a combined open and supported employment service code (5.03) was discontinued on 1 December 2004.
• Changes to linkage processes to estimate service user counts occurred in 2007–08. For more information see Chapter 1 in Disability support services 2008–09.
• The NDIS was launched in trial sites from 1 July 2013, with progressive roll-out to full scheme commencing from 1 July 2016. It is expected that many NDA service users will transition to the NDIS and hence exit from the DS NMDS collection over time. This affects data from 2013–14 onwards, and, as jurisdictions reach full roll-out of the NDIS, data provision to the DS NMDS will cease. In particular:
  • The Australian Capital Territory Government did not collect DS NMDS data in 2015–16 and 2016–17, and was not required to collect data from 2017–18 onwards (as transition to the NDIS in this jurisdiction was completed by the end of 2016–17).
  • New South Wales completed transition to the NDIS during 2017–18 and, because of complexities associated with the transition, only two-quarters of DS NMDS data were collected in 2017–18. As such, data for 2017–18 may be an underestimate. However, it is likely that very few clients only received services in the second half of the year and the first two-quarters are considered largely representative of the full year.

See associated DS NMDS bulletins for more information.