Can a web developer (using Magento community edition) change the google analytics statistics without knowledge or permission of the merchant?
If a developer has an access to the site, he can change GA code. But if the code is correct, that is not the case.
Other ways the statistics can be changed via GA account:
- creating different filters
- changing some set-up settings
In order to do that in a Google Account, a developer should be given an "Edit" Permission to your GA Account via User Management. If he doesn't have an access, he can't do any changes.
As for your site, I would recommend logging all admin's actions to be sure everything is done correctly. You can use our Admin Actions Log extension for that.