23 September 2021
Paul Jones
[FYI request #16538 email]
Tēnā koe Paul Jones
Information request: Mobile phone tracking by Data Ventures
Thank you for your recent email, to the Office of the Privacy Commissioner, requesting
information under the Official Information Act 1982. The Office of the Privacy Commissioner
transferred your request to Stats NZ on 2 September 2021.
With respect to mobile phone data used to generate the Population Density Model, you have
asked to be provided with information discussing:
1) The method of how the mobile phone location data is collected,
2) How the collected data is anonymised.”
The Population Density Model, developed by Data Ventures (the commercial arm of
Statistics New Zealand) provides hourly estimates of population mobility in New Zealand
using pre-aggregated and pre-anonymised mobile phone data, complemented by modelling
of the New Zealand population.
Telecommunications companies Spark and Vodafone provide Data Ventures with counts of
mobile phone devices at cell towers across New Zealand, to provide a snapshot of
population density changes in a given area on an hourly basis. Data Ventures converts the
total device count into population counts, which includes taking into consideration that some
New Zealanders have multiple mobile phones while others do not own any mobile phones.
Maintenance of individual privacy is a serious consideration through this process. Data
Ventures ensures all data is aggregated and anonymised by Spark and Vodafone before
being provided. No individual or identifiable data is provided to Data Ventures and no
individual mobile devices or movements of an individual are tracked through the process.
Any low counts of mobile devices in a location are suppressed. For these reasons, privacy of
individual movements and mobile phone usage is assured.
Data Ventures works closely with the Privacy Commissioner to ensure that data is not used
in a way that threatens the rights of New Zealanders. Further information on how privacy is
protected in the Population Density Model can be found in the Privacy Impact Assessment at
thi
s link. The methodology used has been endorsed by Office of the Privacy Commissioner.
Thank you for taking the time to write, and I hope you find this information useful.
Ngā mihi nui
Kate Satterthwaite
Senior Manager, Executive and Government Relations
Stats NZ