About DWI

Background

The purpose of this project was to construct a broad measure of wellbeing for people with disability that reflects their views on what is important in life. This study created an index that measures the comparative performance of service and support delivery. A valid summary measure is anticipated to promote quality choices for people with disability. The study was supported by the National Disability Insurance Agency (NDIA), an independent statutory agency that implements the National Disability Insurance Scheme (NDIS) for people with a significant and permanent, or likely to be permanent, disability. 

What matters to people with disability: the multi-stage project 

From 2021 to 2024, we conducted a multi-stage project to develop a preference-based wellbeing index for people with disability in Australia – the Disability Wellbeing Index (DWI). Stage 1 of the project developed a classification system for the index, and Stage 2 developed scoring algorithms. 

In Stage 1, we reviewed the existing quality of life and subjective wellbeing measures available in addition to disability or wellbeing frameworks used in Australia and five other similar countries. Preliminary analysis was also conducted on NDIS participants’ outcome data (n=52,569). A set of individual items and 12 broad aspects of life (domains) were developed for use in subsequent stakeholder consultations and qualitative studies with adults with disability and separately with young people with disability. 

Based on feedback received from stakeholder consultations, qualitative studies, and the Victorian Advocacy League for Individuals with Disability (VALID), an initial classification system was created in October 2022, with 35 items within 13 conceptual life domains. 

Defined principles guided the selection process of a set of final items. This helped create a more concise index that could monitor and track the subjective wellbeing of people with disability. According to these principles, the items should be: 

  • Reflective of outcomes that are important to people with different types of disabilities, with varying levels of functional capacity, and who reside in different regions across Australia 

  • Easy to understand 

  • Psychometrically valid and reliable 

  • Sensitive and responsive to differences in the quality and quantity of services and supports provided. 

A cross-sectional online survey was conducted from October to December 2022 with two cohorts (Young People 15-24 years old and Adults 25 years old and over) of NDIS participants to explore the preliminary psychometric properties of the initial set of items, and to facilitate the process of selecting the final items for a concise DWI. Three hundred ninety-two respondents, including NDIS participants or parents and caregivers as proxies, formed the Young People cohort, and 1,255 respondents formed the Adult cohort.

Creating a concise, valid measure 

The selection of DWI items involved the following key analyses: 

  • Exploratory factor analyses to identify the underlying relationships that empirically group the initial set of 35 items 

  • Item selection within each of the identified 7 latent factors for each cohort 

  • Response patterns and the importance ratings for the 35 items 

  • Correlations and explanatory power of the 35 items with global quality of life and life satisfaction scores 

  • Test-retest reliability of the 35 items with a sub-sample of respondents 

  • Consultations with people with disability and policymakers to ensure the final items chosen for the DWI were important to people with disability and relevant for informing policy. 

Selecting the Disability Wellbeing Index items 

The final Disability Wellbeing Index 

There are 14 items in the DWI that cover 10 of the initial 13 conceptual life domains. The DWI items align closely with the outcome domains from Australia’s Disability Strategy 2021-2031 Outcomes Framework, and the NDIS Outcomes Framework. This is demonstrated in the concept map below. Plain English and Easy English versions of the DWI are available. The second stage of the DWI project involved surveying the Young People and Adult NDIS participant cohorts to understand the relative importance of the DWI items. 

For more information about the Disability Wellbeing Index, you can read the full DWI Report. To use the DWI, please register to download the Standard or Easy English versions. You can access the user manual here.