What methods can be used to verify the effectiveness of changes in the user interface?

Methods to confirm the effectiveness of user interface changes include:

• A/B testing — dividing users into groups where one sees the old interface and the other — the new one, and comparing key metrics (conversions, time on screen, number of errors).
• Usability testing — observing real users performing tasks with the new interface, collecting feedback, and identifying issues.
• User behavior analytics — collecting interaction data (clicks, scrolls, transitions) using analytics tools (e.g., Firebase Analytics).
• Surveys and interviews — obtaining qualitative feedback from users about their perception and convenience of the interface.

An example of A/B testing in Android can be implemented through Firebase Remote Config, switching the interface for different user groups.