AustraliaVICBlackburnSt Thomas the Apostle School

St Thomas the Apostle School

CatholicPrimaryPrep-6
Blackburn, VIC 3130 · Major Cities
03 9878 8268
Students185enrolled
Ratio1:12.4student:teacher
SEIFA9/10advantage decile
Community Profile
1130
ICSEA (+130 vs avg)
SEA Top ¼51%
SEA Bottom ¼3%
SEIFA Decile9/10
Indigenous0%
LBOTE15%
St Thomas the Apostle

Socio-Educational Advantage — ICSEA

ICSEA (Index of Community Socio-Educational Advantage) measures the socio-educational profile of this school's community — not the school itself. The national average is 1,000. It is calculated from parental occupation, parental education, geographic remoteness, and Indigenous enrolment proportion.

ICSEA Score1130
800 (most disadvantaged)Well above average1200 (most advantaged)
SEIFA IRSD Decile
9/10
least disadvantaged areas nationally
SEIFA IRSD Score
1100
Area-level index (ABS 2021)
ICSEA: ACARA (2025). SEIFA: ABS Census 2021.

Community Composition

With 51% of students from the top socio-educational quarter, St Thomas the Apostle School draws from a markedly more advantaged community than the national average. This concentration at the top of the ICSEA distribution is reflected in its ICSEA score of 1130.

The chart below shows the proportion of students at St Thomas the Apostle School from each socio-educational advantage quarter nationally. The white reference line marks 25% — the expected value if students were distributed evenly across quarters. Deviation from 25% in any quarter indicates a skewed community intake. The school draws predominantly from the top quarter.

Top quarter
+26pp above avg51%
National average: 25% in each quarter
Upper middle
+7pp above avg32%
National average: 25% in each quarter
Lower middle
-11pp below avg14%
National average: 25% in each quarter
Bottom quarter
-22pp below avg3%
National average: 25% in each quarter
Source: ACARA (2025). National average: 25% per quarter.

Why Community Composition Matters

ICSEA is not a quality ranking

ICSEA measures the community a school serves — not how well the school teaches. Two schools with identical ICSEA scores can have dramatically different teaching quality, culture, and outcomes. ICSEA is context, not verdict.

Always compare like with like

Comparing NAPLAN results between schools with different ICSEA scores is comparing communities, not schools. For meaningful comparison, look at schools within 30–40 points of each other on the ICSEA scale.

The composition shift over time

A school's community composition can shift significantly as a suburb gentrifies or a catchment area changes. A school that was below average in ICSEA a decade ago may now be serving a very different community — and vice versa.

SEIFA supplements ICSEA

SEIFA IRSD measures the geographic area around the school (from Census data). It provides a complementary view — especially useful for understanding schools in gentrifying or rapidly changing neighbourhoods where ICSEA may lag behind the on-the-ground reality.