Hi Fenne,
As you mentioned, Ethica on iOS requires GPS permission even if you don’t intend to collect GPS data. That’s because in order for the Ethica iOS app to collect any background data (in your case, screen state), it needs to remain active in the background. So when you close the app, it should continue to operate and check the screen state change and report it.
In order to do that, the app requires to have GPS permission, so it can remain active in the background. If the user refuses the GPS permission, Ethica will be terminated as soon as you turn off your screen to close the Ethica’s app, and it cannot collect the required data.
Note that if you don’t intend to collect GPS, Ethica will not record GPS data. It will still ask for the GPS permission and uses this permission to work in the background, but does not collect any GPS data.
I understand that this still might be a bit confusing. Incidentally, in our current workshop on health research using Ethica, we did discuss this issue yesterday. The videos of the workshop will be out in the next couple of weeks and we will mark the section that this issue is discussed. That can very well clarify why such permission is required.
Hope this helps,
Mohammad