The Deputy Privacy Commissioner (DPC) has warned the public to take care over merging publicly available data sets, after a popular website was found to be in breach of the Privacy Act.
The creators behind the once-popular website 'What Does My Landlord Own' (WDMLO) pulled data from two different Government data sets, using an algorithm, to display property owners and their address(es).
They made the WDMLO site using data from Toitū Te Whenua Land Information New Zealand (LINZ) - publicly available information.
"The WDMLO algorithm used to manipulate the data for publishing on the website created information that was inaccurate," said Liz MacPherson, the Deputy Privacy Commissioner.
She said people were falsely identified as the owners of properties they didn't actually own.
"Our office received complaints from people reporting emotional and reputational harm," MacPherson added.
It was an example of the "perils" of merging datasets, she said.
WDMLO launched in February 2023, and it was wildly popular - but the DPC's office started getting complaints about the information on the site shortly after.
Accuracy issues with the data arose due to people with shared common names - and the data didn't differentiate between them.
In June, MacPherson said she believed the WDMLO tool was in breach of the Privacy Act - and on Wednesday she confirmed they were.
WDMLO tried to fix the site's algorithm, but the DPC wasn't satisfied.
The DPC commented on the case to give a warning to the public in an ever-more data-saturated world.
"This is a valuable lesson for everyone who uses data."
