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Confidentialised unit record files (CURFs)

Confidentialised unit record files (CURFs) are unit record data that have been modified to protect the confidentiality of respondents while also maintaining the integrity of the data. Modification involves applying methods such as top-coding, data swapping, and collapsing categorical variables to the unit records. The end result is a dataset that can be made available to researchers.  

Application process

CURFs can be accessed through the following process. Please contact us if you need help at any stage:

  1. Complete the CURF application form and email to, along with up-to-date CVs for each researcher named in the application.
  2. Statistics NZ will assess the application and will ask you to provide further information if necessary.
  3. If the application is approved: 
    • the appropriate CURF licence must be signed by a person authorised to sign on behalf of the researcher's organisation 
    • each researcher who will have access to the CURF must sign the appropriate researcher undertaking 
  4. The CURF is supplied to the lead researcher.  

Assessment criteria

All access to microdata is at the discretion of the Government Statistician.

Consideration will be given to applications for CURFs that meet the following criteria:

  • The research is for a statistical purpose. 
  • The researchers have a proven history of research, or will be supervised by someone with a proven history of research. 
  • The researchers have the support of the organisation that employs them (eg, government department, university, or independent research firm).
  • The organisation supporting the research is based in New Zealand.
  • The researchers for the project using the CURF are based in New Zealand.

Methods of access

Once the application is approved, CURFs can be downloaded via secure internet access. Researchers must keep the CURF secure and ensure that the CURF is only accessible to approved researchers. Researchers can use the CURF at their workplace but data cannot be stored on a laptop, memory stick, or other portable device. All copies of the CURF data must be destroyed at the end of the research project.

CURFs are licensed for a 12-month period. The researcher can request a licence extension at the end of this period if further use is required.


Licences and costs

Access to CURF is free and a licence is generally issued for a 12-month period.

Advice to applicant free
One CURF (12-month licence period) free
Two or more CURFs (12-month licence period) free
Extension of use of CURF beyond 12-month licence period free 

Available CURFs

You can view a list of available CURFs here.

Download user guides

You can download PDF versions of some user guides for confidentialised unit record files.

Provide feedback or make a complaint

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Updated 5 March 2020

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