What is Attribution window?

An attribution window is the lookback period during which an ad platform credits a conversion to a prior ad touchpoint. Meta's standard is 1-day-view + 7-day-click; Google Ads defaults to 30-day-click for Search and 30-day-click + 1-day-view for Display; TikTok defaults to 1-day-view + 7-day-click. Attribution windows matter for AI UGC creative testing because they govern how soon you can read a creative's performance and how comparable two creatives' CPAs really are. Short attribution windows (7-day-click) under-credit creatives that drive view-through brand impact; long windows (30-day-click) over-credit creatives that ran before the conversion-causal touchpoint. iOS 14.5+ ATT and the gradual cookie deprecation pushed attribution windows shorter — combined with platform-side modeling (Meta's Advantage+ modeled conversions, Google's data-driven attribution) to fill the gap. For creative ops, the rule is: hold attribution window constant across all comparisons, and read CPA on a fixed window for fair creative testing.