SEIFA 2021 – Summarising Socio-Economic Conditions

With the recent release (April 2023) of the 2021 Socio-Economic Indexes for Areas (SEIFA), we have been able to work up and integrate all of the ABS Census 2021 data within OneMap.

All 4 deciles of the SEIFA dataset can be visualized and filtered, namely:

• Disadvantage (IRSD)
• Advantage and Disadvantage (IRSAD)
• Education and Occupation (IEO)
• Economic Resources (IER)

The SEIFA dataset has also been integrated into the ANALYSER tool so users can summarize and extract SEIFA details for their own Study Areas.

As part of this update we made the decision to also include 2016 – 2021 SEIFA Change as a dataset for our users to explore.

It is important to note that this was only done after due understanding and consideration was given to the ABS’s own documentation of the latest release; as documented and listed at the bottom of this document.

As advised by the ABS, Deciles are mapped and compared in the Change dataset and any areas of boundary change/missing data have been excluded from the change layer.

Given the nature of the data and the SEIFA methodology it is important to note that change in this layer represents, change relative to all other areas.
Indeed, one area might receive a higher raw SEIFA score but that a pervious year but due to performance of other areas fall into a lower decile.

Read the ABS’s own documentation on the SEIFA Methodology here.
https://www.abs.gov.au/methodologies/socio-economic-indexes-areas-seifa-australia-methodology/2021

Change between 2016 and 2021

• SEIFA 2021 largely uses the same method as SEIFA 2016.
• Where available, SEIFA 2021 uses the same candidate variables as SEIFA 2016.
• The Dwelling Internet Connection data item was not collected in the 2021 Census, so the NONET variable could not be used.
• Occupation variables are based on the Australian and New Zealand Standard Classification of Occupations (ANZSCO).
• Variables using cut-off values as part of their specification, such as high and low income (INC_HIGH and INC_LOW), were updated.
• The only processing change was to start from confidentialised (instead of unconfidentialised) area level counts. Using confidentialised area level counts did not have a significant impact on the results, and appropriate comparisons to 2016 results are still valid.

 Time series
The indexes are designed to compare the relative socio-economic characteristics of areas at a point in time, not to compare areas over time. There are several issues that make longitudinal or time series analysis of SEIFA difficult to interpret.

• The constituent indicators and indicator weights for each index are likely to have changed.
• The geographic boundaries and numbers of relevant small areas may have changed.
• The distribution of the standardised index values will have changed (e.g., a score of 800 does not represent the same level of disadvantage in different years).
• There are changes in the way the indicators are defined.

If comparisons over time are made, the use of deciles or percentiles is recommended rather than ranks or scores.