Socio-Economic Decile

Socio-economic decile (also known as Socio-economic decile band or simply decile) is a widely used measure of socioeconomic status in New Zealand education, primarily used to target funding and support to more needy schools.

A school's socio-economic decile is recalculated by the Ministry of Education every five years, after each Census of Population and Dwellings using data collected during the census. Current deciles came into force in 2008 following the 2006 census. Following the 2013 census (delayed two years due to the 2011 Christchurch earthquake), work started to determine new school deciles in time for the beginning of the 2015 school year. They are calculated between censuses for new schools and merged schools, and other schools may move up or down one decile with school openings, mergers and closures to ensure each decile contains 10 percent of all schools.

Before the deciles are calculated, Statistics New Zealand calculates the following factors in each individual meshblock (the smallest census unit, consisting of about 50 households each), disregarding any household in the meshblock that does not have school-aged children:

Each school provides a list of the addresses of its students to determine which meshblocks are used. For each of the five factors, the average for the school is found by adding together the factor in each of the applicable meshblocks, adjusting for the number of students at the school living in each meshblock. All schools in New Zealand are then listed in order for each factor, and given a percentile for that factor. The percentiles for each factor are then added together to give a score out of 500. When the score is ordered, the list of schools is divided into ten, giving one of the ten deciles.

This gives a broad measure of the relative poverty, or aggregated socio-economic (or social class), of the parents or care-givers of students at the school, with decile 1 schools being the 10% of schools with the lowest socio-economic communities and decile 10 schools being at the other end of the scale.

Note that some types of schools acquire a decile rating regardless of the socioeconomic status of the school community. For example, teen-parent units always "belong" in decile 1, because of the inherent effect teenage pregnancy and parenthood has on teen parents' socioeconomic status, regardless whether the teen-parent unit is in a high SES area or attached to a high-decile school.

...
Wikipedia