Decile ratings

What is a decile rating?

A school’s decile rating indicates the extent to which it draws its students from low socio-economic communities.
For example, Decile 1 schools are the 10 percent of schools with the highest proportion of students from low socio-economic communities, whereas decile 10 schools are the 10% of schools with the lowest proportion of these students. A decile does not indicate the overall socio-economic mix of the students attending a school or measure the standard of education delivered at a school.

Each state and integrated school, is ranked into a decile on the basis of a socio-economic indicator. The indicator is based on Census data for households with school-aged children in each school’s catchment area.

When are deciles recalculated?

All school deciles are recalculated by the Ministry following each Government  Population and Dwelling Census.

What does the decile rating affect?

Within a schools operational funding, decile ratings determine the allocation of:

  • Targeted Funding for Educational Achievement (TFEA) 
  • Special Education Grant (SEG) 
  • Careers Information Grant (CIG).

Can the decile rating be reviewed?

Each year boards can seek a review if they believe that their roll profile has changed since the last national review. The annual review period is advertised in the Education Gazette at the end of July / beginning of August, with the deadline for review applications typically being the beginning of October.

How the decile is calculated

The following table describes the decile calculation process:

Stage Description
1 Each school provides all student addresses to the Ministry.
2 Student addresses are assigned to the smallest Census areas called meshblocks. A meshblock contains around 50 households. Only Census information for households with school-aged children is used. The number and percentage of students from each meshblock is determined.

The meshblock is examined against the five following socio-economic factors:

Household incomes

The proportion of households with equivalent income (adjusted for the number of adults and children in the household, and the age of the children), in the lowest 20 percent nationally. Households with a member who is unemployed are usually not included in this group nor are all households supported on a benefit.


The percentage of employed parents in occupations that are at skill levels 4 or 5 (of the 1 to 5 levels in the Australia and New Zealand Standard Classification of Occupation (ANZSCO)). These include all labourers, all machine operators and assemblers, and others who work in occupations at these lower skill levels irrespective of the sector/type/profession involved.

Household crowding

The percentage of households with an equivalised crowding index greater than one. This index is the proportion of household members per bedroom adjusted for the presence of children under 10, every two of whom are assigned to share a bedroom; couples, and others are each assigned their own bedroom.

Educational qualifications

The percentage of parents with no tertiary or school qualifications.

Income support

The percentage of parents who directly (ie not as a partner) received a Domestic Purposes Benefit, Unemployment Benefit or Sickness and Invalid’s Benefit in the previous year.

4 The five census factors are weighted by the number of students from each meshblock. This means that meshblocks where only a few of a school’s students live will have little impact on its decile, while those having more will have a greater impact.
5 Schools are ranked in relation to every other school for each of the five factors and receive a score based on the percentile they fall into.
6 The five scores for each school are added together (without any weightings) to give a total. This total gives the overall standing of the school in relation to all other schools in the country.

Schools are then placed into ten groups called deciles, each having approximately the same number of schools.

Content last updated: 10 November 2014