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Average Session Length (Mobile)


Level 1

whats the reasoning behind the First Launches being deducted from Launches in this calculation:

Total session length / (Launches - First Launches)


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1 Reply


Community Advisor

"Total Session length" is actually based the "Previous Session Length" in the Mobile SDK... so if this is the first time the app is launched, there is no "Total Session length" available. 


So let's break this out:


First Session

  • First Launch and Launch event triggered
  • Page A
  • Page B


Session 2

  • Launch event triggered
  • Previous Session Length sent  (example 1:45)
  • Page C
  • Page D


Session 3

  • Launch event triggered
  • Previous Session Length sent (example 4:28)
  • Page E
  • Page F



Technically, 1:45 + 4:28 (6:13) should only be divided by 2, not 3, so "removing" first launches seems an easy way to do this... but technically, if that first launch was a year ago, and you are looking at this month, I am not sure how this would technically work... it sounds like an oversight on the math to be honest....