How the Equity Index works

To work out each school’s Equity Index number, our statistical model uses information held in Stats NZ Integrated Data Infrastructure (the IDI). This is made up of administrative data provided by other government agencies.

Data in the IDI is de-identified. This means information like names, dates of birth, and addresses have been removed. Numbers that can be used to identify people, like IRD and NHI numbers, are encrypted (replaced with another number).

Stats NZ Integrated Data Infrastructure (IDI) – Statistics New Zealand(external link)

The model

  1. The model looks at cohorts of children from the last 20 years, who have already been through the school system and how, at different ages, various socioeconomic factors impacted their achievement at NCEA levels 1 and 2.
  2. It then looks at the socio-economic characteristics of students enrolled at schools for the last three years to identify which of those factors are present in their lives.
  3. Student numbers are averaged at an individual school level to produce an EQI number for each school between 344-569.

While most students will face challenges and obstacles at some point during their time at school, a higher EQI number indicates that a school has students facing more or greater socio-economic barriers.

Model and key resources on the Equity Index

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