I recently conducted an A/B experiment using Firebase to analyze the Day 1 retention rates for version 1.2 of my app. After analyzing the results, Firebase reported a Day 1 retention rate of 28% for baseline users and 33% for variant A users, averaging around 30%.
However, when I cross-checked these results with Google Analytics 4 (GA4) for the same users and the same period of time, GA4 reported a Day 1 retention rate of 21%.
I'm curious about the reasons behind this discrepancy between Firebase and GA4.
I would appreciate any insights or suggestions on how to reconcile these discrepancies and ensure accurate measurement of Day 1 retention rates across both platforms.
Thank you in advance for your help!