Definition Attribution windows are defined differently on each platform. Google Ads customizes at the conversion action level. Meta Ads offers 1d/7d/28d click + 1d view combinations. Narrower windows lower conversion count; wider windows raise it.
How it works When a user clicks the ad or receives a view, a cookie is assigned. If a conversion occurs within the defined window, the ad is credited. After the window closes, the conversion is not tied to the ad. iOS 14.5 ATT (App Tracking Transparency) affected view windows. Modeled conversion increasingly replaces cookie-based attribution.
Where you see it in Scope Trends The **Attribution Model Analysis** report compares conversion count across window settings. The **Platform Comparison** report harmonizes Google and Meta window differences.
Frequently asked questions **Does changing the attribution window rewrite historical data?** In Google Ads, window changes for new conversion actions apply forward only. For historical data, a separate attribution report opens.
**Which window is correct?** Industry-dependent. Short sales cycles use 7 days; long B2B uses 90 days.