Income
Individual income quartiles
About this topic
Individual income quartiles group people aged 15 years and over into four evenly sized income ranges so the distribution of personal income can be compared objectively across areas and over time. The quartile method focuses on relative position in the income distribution rather than raw dollar brackets.
This topic is useful because direct income amounts are affected by inflation and wider economic change. Quartiles provide a clearer way to compare whether an area is becoming relatively lower, middle, or higher income over time.
Interpretation notes
- This is a derived distribution of personal income for people aged 15 years and over, with each quartile representing a quarter of the income distribution.
- Quartiles show relative position rather than fixed dollar brackets, which makes them more robust for comparisons over time.
Key insight
In 2021, the medium-low income quartile held the largest share among residents aged 15 and over in Robertstown, accounting for 38.7%.
Section overview
Individual income quartiles
Robertstown - Persons aged 15+ (Usual residence)
This table summarises individual income quartiles for Robertstown in 2021 for persons, with comparison against Goyder (DC) and change since 2016.
Individual income quartiles snapshot
2021 distribution by category for Robertstown, with comparison markers for Goyder (DC).
Lowest group
2021 count
75
% of total
37.7%
Change from 2016
+16.2pp
75
37.7%
+16.2pp
Medium lowest
2021 count
77
% of total
38.7%
Change from 2016
+20.4pp
77
38.7%
+20.4pp
Medium highest
2021 count
31
% of total
15.6%
Change from 2016
-7.2pp
31
15.6%
-7.2pp
Highest group
2021 count
16
% of total
8.0%
Change from 2016
-29.4pp
16
8.0%
-29.4pp
Chart view
Individual income quartiles change
Absolute change in category counts between 2016 and 2021.
Lowest group
-177
+16.2pp
Medium lowest
-138
+20.4pp
Medium highest
-236
-7.2pp
Highest group
-422
-29.4pp
Data table
Individual income quartiles for Robertstown. Individual income quartiles. 2021 and 2016 counts, percentages, and change compared with Goyder (DC).
| Category | 2021 | 2016 | Change | |||||
|---|---|---|---|---|---|---|---|---|
| Count | % | Goyder (DC)% | Count | % | Goyder (DC)% | Count | pp | |
| Lowest group | 75 | 37.7% | 31.3% | 252 | 21.5% | 25.5% | -177 | +16.2pp |
| Medium lowest | 77 | 38.7% | 37.0% | 215 | 18.3% | 36.3% | -138 | +20.4pp |
| Medium highest | 31 | 15.6% | 20.1% | 267 | 22.8% | 23.5% | -236 | -7.2pp |
| Highest group | 16 | 8.0% | 11.6% | 438 | 37.4% | 14.6% | -422 | -29.4pp |
| Total persons aged 15+ | 199 | 100.0% | 100.0% | 1,172 | 100.0% | 100.0% | -973 | 0.0pp |