The monthly sessions in Audience overview doesn't match with the monthly segmented sessions
I pulled a report from Audience overview and another one from Acquisition channel overview. I found that the monthly sessions in Audience overview doesn't match with the one in Acquisition channel overview. Here is the example (dumb numbers).
Audience overview report:
Nov - 2015 7890
Dec - 2015 8964
Jan - 2016 8775
Feb- 2016 7998
acquisition channel overview report:
Nov - 2015 8643
Dec - 2015 8664
Jan - 2016 9275
Feb- 2016 6998
The total sessions for the whole period (4 months in this example) is approximately the same but monthly data can have variance up to 20%.
Does anybody know what caused the variance in monthly session data? Thanks!
Re: The monthly sessions in Audience overview doesn't match with the monthly segmented sessions[ Edited ]
March 2016 - last edited March 2016
Acquisitions are based on where they came from and audience is who they are (demographics) and the devices they used. These sessions can never be the same as a user may come from multiple channels and count as multiple sessions, however at the end of the day they are only a single audience unless they switch device.
On another note there is sampling that takes place at a different rate depending on data being sourced so this caused discrepancies in most data figures. You can come back tomorrow and compare the same data and sometimes the data is different.
Re: The monthly sessions in Audience overview doesn't match with the monthly segmented sessions
Thanks a lot for your reply.
My understanding is that for the total sessions for the whole site should be about the same no matter how we slice the data (by acquisition or by channel). My presumption is if a user initiated multiple sessions in one day, each session is counted independently. For example, if a user goes directly to site in the morning and then came back to site from Google search in the evening, there are 2 sessions for that user for that day. The total sessions in audience should be 2. In the acquisition portal, there is 1 session for Direct and 1 session for Search. The total is still 2. Please let me know if I am wrong about this.
Sorry if my problem description is not accurate enough. The specific question is that why there is large monthly variance although the total sessions for a specific period (let's say 3 months) are about the same? Does this more relate to the data sampling?