(A) Clicks and Impressions are directly imported from Campaign Manager and Sessions are reported when the user visits the site from a Campaign Manager Campaign.
(B) It’s possible that the Campaign Manager Advertiser is driving traffic to multiple web properties.
(C) You’ve enabled ‘Allow manual tagging (UTM values) to override auto-tagging(DCLID values) for Campaign Manager and Display & Video 360 reporting integration.’
(D) Clicks and sessions are recorded differently by different systems.
There are discrepancies because of three main reasons.
(1) The Clicks and Impressions data are directly imported from Campaign Manager but the Click-through Sessions data is reported only when a user visits your website after clicking on a Campaign Manager ad. The clicks data will generally be higher.
(2) If you’re running using multiple websites with a Campaign manager Advertiser then there will be a noticeable difference in the clicks and sessions data.
(3) Different systems follow different models and systems to record clicks and sessions data. If there is a difference in the system how clicks and sessions are recorded then naturally there will be a difference in the recorded data.
This question is a part of the Assessment 3 exam of Getting Started with Google Analytics 360. You can find all the answers to this exam in our Getting Started with Google Analytics 360 Assessment Answers page.