Conceptual framework

For SEIFA 2021, the concept of relative socio-economic advantage and disadvantage is the same as that used for SEIFA 2006, 2011 and 2016. That is, the ABS broadly defines relative socio-economic advantage and disadvantage in terms of people's access to material and social resources, and their ability to participate in society. This is described as ‘broadly defined’ in recognition of the many concepts that have emerged in the literature to describe advantage and disadvantage. The dimensions included in SEIFA are guided by international research, given the constraints of Census data. The Census does collect information on the key dimensions of income, education, employment, occupation, housing, and other miscellaneous indicators of advantage and disadvantage. Variables have been selected from these dimensions and are discussed further in the description of candidate SEIFA variables.

Another point to note is that SEIFA measures relative advantage and disadvantage at an area level, not at an individual level. Area level and individual level disadvantage are separate though related concepts. Area level disadvantage depends on the socio-economic conditions of a community or neighbourhood as a whole. These are primarily the collective characteristics of the area’s residents, but may also be characteristics of the area itself, such as a lack of public resources, transport infrastructure or high levels of pollution. However, it is important to remember that SEIFA is restricted to the information that is included in the Census.

It is recommended that SEIFA users consider their research interests, the definition of each SEIFA index and the variables included in each index to determine the appropriate index to use. The ABS produces four indexes, each summarising a different subset of Census variables, because users may be interested in different aspects of socioeconomic advantage and disadvantage. Defining the concept behind each of the four indexes provides more information on the indexes included in SEIFA.

This section gives a description of the concept behind each of the four indexes. For a list of the variables included in each index, refer to the technical details for each index: variables and loadings.

The IRSD summarises variables that indicate relative disadvantage. This index ranks areas on a continuum from most disadvantaged to least disadvantaged. A low score on this index indicates a high proportion of relatively disadvantaged people in an area. We cannot conclude that an area with a very high score has a large proportion of relatively advantaged people, as there are no variables in the index to indicate this. We can only conclude that such an area has a relatively low incidence of disadvantage.

The IRSAD summarises variables that indicate either relative advantage or disadvantage. This index ranks areas on a continuum from most disadvantaged to most advantaged.

An area with a high score on this index has a relatively high incidence of advantage and a relatively low incidence of disadvantage. Due to the differences in scope between this index and the IRSD, the scores of some areas can vary substantially between the two indexes. For example, consider a large area that has parts containing relatively disadvantaged people, and other parts containing relatively advantaged people. This area may have a low IRSD ranking, due to its pockets of disadvantage. However, its IRSAD ranking may be moderate, or even above average, because the pockets of advantage may offset the pockets of disadvantage.

The IER summarises variables relating to the financial aspects of relative socio-economic advantage and disadvantage. These include indicators of high and low income, as well as variables that correlate with high or low wealth. Areas with higher scores have relatively greater access to economic resources than areas with lower scores.

The IEO summarises variables relating to the educational and occupational aspects of relative socio-economic advantage and disadvantage. This index focuses on the skills of the people in an area, both formal qualifications and the skills required to perform different occupations. A low score indicates that an area has a high proportion of people without qualifications, without jobs, and/or with low skilled jobs. A high score indicates many people with high qualifications and/or highly skilled jobs.