Time on Site: Adobe vs. GA4

[dwang1109]

I'm trying to compare the time on site for two different websites. One is using GA4 and one is using Adobe Analytics. I'm seeing a dramatically different time on site in GA4 than Adobe. Does anyone know what are the differences in time on site in Adobe vs average engagement time in GA4?

[Jennifer_Dungan]

Honestly, I don't particularly trust either

Since neither one use a heartbeat or take "page minimized" or "tab not focused / active" into account"... 

As a "general" concept, is time spent going up, going down, staying constant over a time range is about all I would use the data for....  for actual time spent... no.  Basically, I tell people in my organization not to trust this value too much.... Also, the last page of the visit (and that means all pages that are "single page visits") are not included in those time spent metrics....

But at this time, I am not sure that GA4 has their calculations working properly yet....the numbers seem completely out of whack to me... 

[dwang1109]

I completely agree. It's more of a directional metric than a definitive one. 

[yuhuisg · Accepted solution]

For GA4, I believe you're referring to the User Engagement metric that is described at https://support.google.com/analytics/answer/11109416?hl=en. In that documentation's example, you can see that time spent is measured with every hit that is sent to GA4. Notice in that example that when there is a "scroll" event (within the same page), engagement time is measured too.

On the other hand, AA measures time spent by the difference between 2 timestamps, as documented at https://experienceleague.adobe.com/docs/analytics/components/metrics/time-spent.html?lang=en. So if the user views one page in your website only, then even though the user scrolls in that page, the time spent for that page will still be 0 because there is no timestamp from a second page to calculate a duration.

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As you've probably discovered from this situation, it's important to understand the definitions that are used by different analytics platforms for even the same terms. Heck, even something as basic as "visits" (AA) vs "sessions" (GA) have different definitions. Do your best to understand the definitions from the respective platforms' documentation, then apply your understanding to the data that you see in your reports.

All the best.