Attribution Window

The attribution window is the time period after someone clicks or views an ad during which a resulting conversion is still credited to that ad.

Wider windows credit more conversions to advertising, which mechanically inflates reported ROAS and conversion counts even if nothing about the campaign's real performance changed. A platform default of a 7-day click / 1-day view window versus a 28-day click window can produce meaningfully different reported results for the identical campaign.

Since iOS 14.5 and the broader privacy shift, platforms have generally shortened default windows and reduced view-through crediting, which is part of why attributed performance metrics dropped industry-wide around 2021 without campaigns actually getting worse.