Set out below are a number of issues that may show discrepancies between DoubleClick and AppsFlyer.
DoubleClick self-reports whereas AppsFlyer ties in-app events to the attribution source within AppsFlyer - which may not always be DoubleClick.
As a result, some conversion events are discarded from the DoubleClick system as invalid/spam activity after they have posted their attribution response to AppsFlyer. In such cases, AppsFlyer may report on these events, but DoubleClick does not.
If you see high numbers of conversions reported in AppsFlyer that are missing from DoubleClick, we recommend running a DoubleClick report on invalid activity to determine whether there is an issue with your inventory.
View-Through Attribution Window
DoubleClick's view-through attribution window is 14 days, while AppsFlyer's default window is 1-day. To minimize the risk of discrepancy, set the view-through window in AppsFlyer to match the the view-through set in DoubleClick's set-up window.