This is a particular problem because the internet, and social media especially, is now such a common source of information.
Social media data can also be used to calculate creditworthiness, despite its dubious relevance.
Indicators such as the level of sophistication in a user’s language on social media, and their friends’ loan repayment histories can now be used for credit checks.
This can have a direct impact on the fees and interest rates charged on loans, the ability to buy a house, and even employment prospects.
There’s a similar risk with payment and shopping apps.
In China, the government has announced plans to combine data about personal expenditure with official records, such as tax returns and driving offences.
This initiative, which is being led by both the government and companies, is currently in the pilot stage.
When fully operational, it will produce a social credit score that rates an individual citizen’s trustworthiness.
These ratings can then be used to issue rewards or penalties, such as privileges in loan applications or limits on career progression.
These possibilities are not distant or hypothetical – they exist now.
Smartphones are effectively surveillance devices, and everyone who uses them is exposed to these risks.
What’s more, it is impossible to anticipate and detect the full range of ways smartphone data is collected and used, and to demonstrate the full scale of its impact.
What we know could be just the beginning.
By Vivian Ng and Catherine Kent. This article was first published by The Conversation