Novice
Navigation is inconsistent, or organized unconventionally according to Material design guidelines for Android.
Competent
Navigation is well-structured/organized and follows conventions appropriate to Android and the product.
Proficient
Navigational hierarchy has been considered and designed to match intended users' mental models of product and information.
Expert
Multiple navigation models have been considered and tested, with clear evidence for how the chosen model matches up with user expectations and mental models.