This publication outlines how SEIFA is constructed and provides guidance on how it should be used and understood.
See SEIFA for general information on SEIFA 2021, and to access the data.
For detailed technical specifications refer to the SEIFA Technical Paper.
SEIFA indexes
SEIFA is a collection of four indexes, each summarising a different aspect of the socio-economic conditions in an area using different Census data:
- the Index of Relative Socio-economic Advantage and Disadvantage (IRSAD) focuses on both advantage and disadvantage
- the Index of Relative Socio-economic Disadvantage (IRSD) focuses on relative socio-economic disadvantage
- the Index of Education and Occupation (IEO) focuses on relative Education and Occupation advantage and disadvantage
- the Index of Economic Resources (IER) focuses on Economic advantage and disadvantage.
The same area may score differently for each index due to their constituent variables.
Advantage and disadvantage
For SEIFA purposes, relative socio-economic advantage and disadvantage is defined as people's access to material and social resources, and their ability to participate in society. The dimensions are constrained by what is collected in the Census; they include income, education, employment, occupation, housing, and family structure.
SEIFA is area based
SEIFA is designed and constructed as an area-based measure. Area-based deciles are calculated by dividing the areas, ordered by disadvantage, into ten equally sized groups. Decile one contains the most disadvantaged areas and decile ten contains the most advantaged areas.
SEIFA geography
The SEIFA scores are initially calculated by Statistical Area Level 1 (SA1).
Scores for higher level geographic areas, such as Statistical Area Level 2 (SA2), Local Government Areas (LGA), Suburbs and Localities (SAL), and Postal Areas (POA) are calculated using population-weighted averages of the SA1 scores. This ensures that the higher-level geographic area scores reflect the size of the population within each contributing SA1.