Business models are built around collecting user data.
Up to 85% of mobile apps are failing to clearly tell their users how their personal information is being used, according to a study by the Global Privacy Enforcement Network (GPEN), a regulatory consortium.
More than half of apps were found to squirrel away basic privacy information, with a third requiring "excessive" permissions, and 43% not altering their privacy information to a small screen.
Simon Rice, group manager for technology at GPEN member the Information Commissioner’s Office said: "Apps are becoming central to our lives, so it is important we understand how they work and what they are doing with our information.
"Today’s results show that many app developers are still failing to provide this information in a way that is clear and understandable to the average consumer."
However the research did show some examples of good practice, including time sensitive notifications to make users more aware of when their data was being collected.
Andersen Cheng, chief executive of security firm SRD Wireless, said: "As it isn’t realistic to assume consumers will read any small print, reputable app developers should make a page one declaration saying what data they are collecting before the consumer even downloads an app."
He added that the business model of many apps meant that "many apps store far more information than they need", and called for bad practice to be shunned by users.