Reply To: The inconsistency in summing session numbers on GA4: What's the reason behind it?

[Alexander]

Hey! So here’s the thing – Google launched GA4 with the idea of saving on servers used for supporting Analytics. In its earlier avatar – Google Analytics Universal Analytics – it was just too feature-packed as a free product.

With GA4, things have changed a bit. We’re talking harsher data retention rules, limitations on dimensions cardinality, stricter sampling, you get the drift. It’s a different ballgame.

Coming to your question, remember that one session can have only one associated channel. What’s likely happening is, GA4 isn’t just adding up the session numbers. That would be too costly processor-wise. Instead, it uses complex algorithms that make the process speedier but less precise. It’s similar to this technique called ‘hyperloglog’ used in data aggregation.

Oh, did I mention? The GA4 interface can be buggy at times.

But hey, there’s a workaround! To make those numbers add up, you can carry out your analytics in a BigQuery export from GA4. Or even better, use a Business Intelligence tool of your choice on the exported data. Hope this helps!