The ‘Session time’ graph under Monitoring > Performance > Client shows incorrect information; In most cases the stats are much lower than what they should be.
This results in discrepancies between data shown in the ‘Average Session Time’ graph under Analytics > Engagement and ‘Session time’ in the Performance tab.
The engagement graph has the average over 1 month, and the client graph has the average per hour, however, I checked myself and if I set both to 7 days there was still a 4 minute difference. Not sure why though.
They are showing you different things tailored to your use case…
The average you are seeing in Monitoring > Performance is the AVG(platform time).
This is NOT a weighted average based on how your sessions are distributed, while the one you are seeing in Analytics > Engagement is weighted by session distribution.
For anything Real-time, we have to tradeoff speed to give you directional data every 1 min, while Analytics we provide you the data every 24 hrs so we have a chance to crunch a lot of numbers.
We did it this way for Performance because of the computation required as well as we breakout each platform individually in Monitoring because if you have a minor but still significant amount of users for 1 platform, you wouldn’t want that platform’s session time to be merged just a total, hidden behind a breakdown dropdown.
When you are publishing a new version, you will want to see if a certain platform is underperforming asap.