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Government Policy, SOSNZ

NZ School Decile Ratings Explained

There is much confusion about what a school’s decile rating means.   It in NO way depicts the quality of the school, the teaching there, or the students’ achievements.   It is merely a way of rating the socio-economic level of a school’s community.

Here is an overview:


A decile is a 10% grouping. A school’s decile rating indicates the extent to which it draws its students from low socio-economic communities.

Decile 1 schools are the 10% 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 (with the exception of health camp schools, regional health schools, and Child, Youth and Family schools), is ranked into a decile on the basis of the indicator. The indicator is based on Census data for households with school-aged children in each school’s catchment area.


– each school provides its students’ addresses to the Ministry of Education.

– the addresses are grouped into what the Ministry call ‘meshblocks’,  which is essentially groups of 50 homes physically close to each other

– the addresses are then measured against the following criteria:

  1. Occupation of people living at that address. (Specifically, 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.)
  2. Household income.  (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% nationally. Households with a member who is employed are usually not included in this group nor are all households supported on a benefit.)
  3. 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.)
  4. Educational Qualifications.  (The percentage of parents with no tertiary or school qualifications.)
  5. 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. It does not include parents receiving the Family Tax Credit.)

– The five census factors are then 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.

–  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.

–  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 put into ten groups, called deciles.

For a full and more detailed explanation, please go to the Ministry of Education’s website.

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  1. Pingback: Decile review causing blunt force trauma | Save Our Schools NZ - November 27, 2014

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