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2021 Disadvantage Index deciles by NSW electorate or Statistical Area Level 1 2021 (SA1)
Select map: View either SA1 deciles (based on ranking all NSW SA1s) or electorate deciles (based on ranking all NSW electorates)
Search: Type an address and select from the list to zoom straight to a location of interest
View details: Click on any area to see its decile, rank, and name or ID
Decile: 1 = most disadvantaged 10% of areas
Rank: 1 = most disadvantaged area
Interactive tables
Interpreting the data
The Disadvantage Index summarises socio-economic disadvantage for an area
Index scores summarise relative socio-economic disadvantage based on many different census variables, with low scores indicating relatively greater disadvantage. For example, an area could have a low score if there are many people with low incomes or many people without jobs. Scores are calculated for areas, not individuals; people living within each area will differ in their socio-economic characteristics.
Index scores are used for ranking areas
| Electorate | Score |
| Average score | 1,000 |
| Albury | 972 |
| Wyong | 957 |
Index scores are on an arbitrary scale, where the average (mean) is set to 1,000 and the standard deviation is set to 100. For example, the 2021 scores for Albury and Wyong indicate they were both relatively more disadvantaged than the average of all electorates. Wyong's score suggests it was relatively more disadvantaged than Albury. However, index scores don’t represent any particular quantity of disadvantage and their main use is for ranking areas. For ease of interpretation, ABS generally recommends the use of rankings and quantiles (such as deciles) instead of index scores.
Deciles are used to group electorates
| Electorate | Decile |
| Albury | 3 |
| Wyong | 2 |
To calculate deciles, electorates are ranked by their index score. The list is then divided into 10 groups (deciles), each representing approximately 10% of electorates, with decile 1 containing the most disadvantaged 10% of electorates. For example, Wyong and 9 other electorates were grouped into decile 2. These electorates were relatively more disadvantaged than the electorates in decile 3.
Disadvantage varies geographically within each electorate
An electorate's decile is a summary of its relative disadvantage, but disadvantage also varies within each electorate. To allow exploration of this variation, the interactive map shows not only the electorate-wide decile but also the deciles calculated for smaller areas known as Statistical Areas Level 1 (SA1s). To calculate the SA1 deciles, Disadvantage Index scores were calculated for each SA1 in NSW, then the SA1s were ranked by their score, irrespective of which electorates they fell in. This NSW-wide list was then grouped into deciles. The pop-up information for each SA1 also lists the name of the larger Statistical Area Level 2 (SA2) of which it is a part.
Index scores can't be compared over time
The Disadvantage Index is not designed for comparisons over time. There are several reasons data from different censuses are difficult to compare, including that the index scores are calculated in different ways for each census. For example, the relative weight (loading) given to each variable differs between censuses. The variables included may also differ; for instance, in 2011 and 2016 the Disadvantage Index incorporated a variable related to internet connection. In the 2021 Census this information was not collected and so the variable was not included in the 2021 Disadvantage Index.
The ABS recommends that if comparisons over time are made, deciles or other quantiles should be used rather than ranks or scores. Time comparisons can often be made for the census variables underlying the indexes, although in some cases the interpretation may be complicated by inflation and changes in threshold values between years (for example for the proportion of people in low-income households).
Deciles don't change much over time, but socio-economic conditions do
Typically the deciles of large areas like electorates don't change much from one census to the next. For example, between 2011 and 2021 Albury moved from decile 4 to decile 3, while Wyong moved from decile 1 to decile 2. Only 2 of the 93 electorates changed by more than 2 deciles between 2011 and 2021 (Holsworthy and Londonderry).
This doesn't mean socio-economic conditions have stayed still since 2011. Most of the individual census variables from which the index is calculated have changed. For instance, between 2011 and 2021 every electorate decreased in the percentage of people whose highest level of education was year 11 or lower.
The index summarises census data only
The dimensions of disadvantage that can be captured by index scores are limited to data available in the census. Other dimensions of disadvantage (such as wealth) are not included. In 2021, the census variables used to calculate Disadvantage Index scores were (in order of their weight in the calculation):
- Percent of people with stated household equivalised income between $1 and $25,999 per year
- Percent of families with children under 15 years of age who live with jobless parents (includes couple and one parent families)
- Percent of people aged 15 years and over whose highest level of education is Year 11 or lower (includes Certificate I and II; excludes those at secondary school)
- Percent of occupied private dwellings where the rent was less than $250 per week (excluding $0 per week)
- Percent of people in the labour force who are unemployed (also known as the unemployment rate)
- Percent of employed people classified as Labourers
- Percent of people aged under 70 who need assistance with core activities due to a long–term health condition, disability, or old age
- Percent of families that are one parent families with dependent offspring only (a dependent child is a person who is either a child under 15 years of age, or a dependent student aged 15-24 years)
- Percent of occupied private dwellings requiring one or more extra bedrooms.
- Percent of employed people classified as Machinery Operators and Drivers
- Percent of people aged 15 years and over who are separated or divorced
- Percent of people aged 15 years and over who have no educational attainment (did not attend school and do not have a non-school qualification)
- Percent of employed people classified as low skill (skill level 4 and 5) Community and Personal Service workers
- Percent of occupied private dwellings with no cars
- Percent of people aged 5 years and over who do not speak English well.
Data is available in the download section for each of these variables for 2011, 2016 and 2021 by electorate and region. Note that the threshold values for variables related to income and rent differed between censuses. The details of these thresholds are available in the download file.
Other SEIFA indexes emphasise different dimensions of disadvantage
This data brief focuses on the Disadvantage Index, but data downloads are also provided for the other 3 SEIFA indexes. Each of the 4 indexes emphasises different Census variables:
- Advantage-Disadvantage (IRSAD): Summarises information about both relative disadvantage and relative advantage.
- Economic Resources (IER): Summarises information related to income and housing. It excludes education and occupation variables. It does not include assets such as savings because this information is not collected in the Census.
- Education and Occupation (IEO): Summarises information about the educational and occupational level of an area. It excludes income variables.
Download the data
A more extensive set of SEIFA data by NSW electorate is available for download as two Excel files. These provide data from:
- Four SEIFA indexes (IRSD, IRSAD, IEO, IER) by NSW electorate (2021 redistribution) and NSW region for all censuses between 2001 and 2021. For each index, the data provided is population, score, rank, decile, min and max.
- Fifteen census variables used in calculating the 2021 Disadvantage Index (IRSD) by NSW electorate (2021 redistribution) and NSW region. For each variable, data is provided for 2011, 2016 and 2021.
Download variable data (Excel)
Further reading
- Australian Bureau of Statistics, Socio-Economic Indexes for Areas (SEIFA) Australia
- Australian Bureau of Statistics, SEIFA methodology
- Digital Atlas of Australia, Index of Relative Socio-Economic Disadvantage (IRSD) 2021 (with indicator profile)
Contact us
Members and parliamentary staff can request research by emailing DPS.ResearchService@parliament.nsw.gov.au. Access Parliamentary Library resources and learn more about us including our service guide on the parliamentary intranet (internal users only). Media contact: media@parliament.nsw.gov.au.
Title: Electorate data: Socio-economic disadvantage
Author: Cristy Gelling
Publication number: Data Brief No. 2024-06
ISSN 2981-8354 (Online)
The NSW Parliamentary Research Service provides impartial research, data and analysis services for members of the NSW Parliament.
© 2024 Except to the extent of the uses permitted under the Copyright Act 1968, no part of this document may be reproduced or transmitted in any form or by any means including information storage and retrieval systems, without the prior consent from the Senior Manager, NSW Parliamentary Research Service, other than by members of the New South Wales Parliament in the course of their official duties.
Any advice on legislation or legal policy issues contained in this publication is provided for use in parliamentary debate and for related parliamentary purposes. This publication is not professional legal opinion.
Published: 24 October 2024