Discrepancy between session duration

  • 5 October 2020
  • 4 replies


I am currently creating an insight to measure the cumulative number of minutes spent on our application (across all sessions).
For some reason, using the events and parameters above, I get two different numbers (session duration based on session end is approximately 40% larger than using session start).

Why is there a difference between these two values? (and are these the wrong parameters to use when trying to calculate the cumulative number of minutes spent in our app?)

4 replies

Userlevel 3
Badge +1



They should give you the same answer, for example, see:

Where the answers might differ though, is if your date range includes this last day, where you have users who are still in the midst of their sessions, the session start and end times may not be the same.

Hope that helps!

@Peishan Thanks for the reply. However, this wouldnt explain the difference in numbers, since the timeframe I am selecting is >6 months. Average session duration is in the order of minutes, so that doesn't explain the 40% difference.
Any other suggestions?

Userlevel 3
Badge +1

Hi Joao, 

Without looking at your data, it’s hard for me to dive into your data to see what the issue is unfortunately. If you’re on a paid plan, you also have the option to contact our Support team for help: Hope that works!

Userlevel 5
Badge +3

@joao_blloc ,

To add on some additional detail about sessions, it’s worth pointing out that a single user can start multiple sessions. Those sessions can occur on the same day, or over several days, weeks, or months. As soon as a "Session End" event is performed, another session can begin with the occurrence of a new "Session Start" event. 

To find the average session duration, and total session duration you would want to aggregate the property, `Session Duration (Seconds)` that comes with the event Session End. 



We would expect that the duration property is the same for both events, but I’d be curious to understand what you are seeing. 

  • How did you configuredSessions? Are they timeout based or event based?
  • Are you seeing more Session Start events than a Session End event? That would still raise a question though of why there would be more of one event than the other, but it may lead us to what may be going on.
  • Can you confirm that you were not tracking events by this name, before Mixpanel started to track these events automatically on your behalf?
  • Do you see a consistent 40% difference? or is this during a specific period of time?
  • Can you tell me what SDK you are using? and what version?