Average time on site vs Average session length (mobile)

[unba2020]

Hello,

I am looking at some of the "time spent" metrics in our mobile app site. 

I read the "Time Spent Overview Guide https://experienceleague.adobe.com/docs/analytics/components/metrics/time-spent.html?lang=en" but still don't really get the difference between the average time on site vs average session length.

Could anyone kindly give me some examples and help?

Thank you so much!

[Garretth · Accepted solution]

Average Session Length (mobile) gets compare to 'Average time on site' but it looks more aligned with the session based metric ‘Time spent per visit (Seconds)’ which is defined as:

“Total seconds spent / (visit-bounces)
Represents the average amount of time visitors interact with a specific dimension item during each visit.”

which is very similar to  ‘Total Session Length / (Launches – First Launches)’  If you think of 'first launch' as a bounce. These are both essentially saying (total time spent)/(# of visit based sessions where time is spent)

[unba2020]

Thank you so much!