Attribution window
An attribution window is the period after someone sees or clicks an ad during which a later conversion still gets credited to that ad. A common setting is a 7-day click, 1-day view window: if a click leads to a purchase within seven days, the channel takes the credit. Outside the window, the conversion goes unattributed to that touch.
This quietly shapes every channel report you read. A long window flatters slow-converting channels and can double-count across platforms; a short one under-credits anything with a considered buying cycle. For a founder spending real money, the practical move is to fix one consistent window across your reporting, know what each ad platform defaults to (they differ, and they self-report generously), and compare channels on the same basis. Otherwise you'll cut a channel that was actually working, or scale one the window inflated.