Appthority only looked at 100 free apps, 50 each on Android and iOS, covering five categories. So, this study may not give concrete evidence on the subject. On the iOS side, it was found that 60% of the iOS apps checked collected location data, 54% collected contacts or e-mail addresses, 60% shared user data with ad networks, and 50% used some sort of single sign-on (Facebook, Twitter, or Google).The first thing that has to be mentioned is that
Android was slightly lower almost across the board with 42% collecting location data, only 20% collected contacts or e-mail addresses, 50% shared data with ad networks, and 50% used single sign-on.
What is a bit more disconcerting though is the fact that none of the iOS apps transferred personal data with encryption, and only 8% of Android apps used encryption. Depending on the apps tested, the data collection may or may not be all that bad, but regardless of the app in question, it is unacceptable for apps to transmit personal data without encryption.
Appthority also says that "less than 1%" of Android apps in the Play Store contain malware, which seems to confirm other numbers we've seen on the subject. But, it's just a bit odd because if Appthority only studied 50 apps, anything less than 2% gives you a fraction of an app, which isn't possible.