Attribution Window

An attribution window (also called a conversion window or lookback window) is the time period after a user interacts with an ad during which any subsequent conversion is credited to that ad. If you set a 7-day click attribution window and a user clicks your ad on Monday and purchases on Thursday, the conversion is attributed to the ad. If they purchase 10 days later, it is not.

Why it matters: attribution windows directly impact how you evaluate campaign performance. A longer window credits more conversions to your ads, making campaigns appear more effective. A shorter window gives a more conservative view. Choosing the right window affects budget decisions: if you shorten your attribution window from 28-day to 7-day click, some campaigns will suddenly show fewer conversions and might get their budgets cut, even though their actual impact has not changed.

Common window types: click-through windows track conversions after someone clicks your ad (typical options: 1-day, 7-day, 14-day, 28-day). View-through windows track conversions after someone sees but does not click your ad (typical options: 1-day, 7-day). Most platforms default to something like 7-day click and 1-day view. Meta Ads defaults to this combination. Google Ads defaults to 30-day click for Search campaigns.

How to choose: shorter windows (1-day click) are best for direct-response campaigns where you expect immediate action (e-commerce flash sales, app installs). Longer windows (7-28 day click) suit considered purchases with longer decision cycles (B2B SaaS, high-ticket items). View-through windows are contentious: they credit conversions to ads people merely saw, which inflates reported performance. Many sophisticated advertisers use view-through data directionally but do not fully trust it.

Platform-specific considerations: Apple's iOS 14.5+ privacy changes forced Meta to limit attribution windows to 7-day click and 1-day view maximum for most campaigns. This made longer-cycle B2B attribution harder to measure within Meta's reporting. Google Ads still supports up to 90-day windows for some campaign types. These platform limitations make cross-channel attribution tools (like Triple Whale, Northbeam, or Rockerbox) more important for getting a complete picture.

Common mistakes: comparing performance across campaigns with different attribution windows. Using the same attribution window for all campaign types (your awareness campaign and your retargeting campaign should likely use different windows). Not understanding that platform-reported conversions use default attribution windows and might not match your analytics or CRM data, which uses its own attribution logic.

Practical example: a B2B SaaS company runs LinkedIn ads promoting a free trial. With a 7-day click window, the campaign shows 15 conversions at $200 CPA. They extend the window to 30 days (available in LinkedIn's reporting) and see 38 conversions at $79 CPA. This makes sense: their product has a multi-week consideration phase. The longer window reveals the campaign's true impact and prevents them from incorrectly cutting a profitable campaign.