GA4 & UA YoY Comparisons
With GA 4, Google shifted focus from a session-based measurement model to an in-depth event-based model. The new data collection model provides more accurate insights into user behavior across platforms.
As Universal Analytics (UA) and GA4 utilize different data models, backward compatibility, and comparison between UA and GA4 data are not offered by Google. For this reason, Milestone Analytics does not support Y-o-Y data comparisons between UA and GA4 data. To compare metrics between GA4 and Universal Analytics and understand why YoY comparisons would not be possible in some cases, click on the article [UA→GA4] Comparing metrics: Google Analytics 4 vs. Universal Analytics.
Note: GA4 data will be available from the day it was set up for your business.